Mercedes have signed Valtteri Bottas as the replacement for recently retired Formula One world champion Nico Rosberg, with Williams confirming the news in their own announcement that Felipe Massa has been persuaded to extend his career by one more season to replace the Finn.

Bottas had been the frontrunner to replace 2016 world champion Rosberg ever since the German announced his shock retirement in December last year, though despite initial reports claiming his replacement would be announced early in the new year, the paddock was put on hold to see who would fill the vacancy with the reigning constructor champions.

On a busy day of motorsport news, Mercedes finally confirmed that Bottas would partner Lewis Hamilton for the 2017 campaign, although full confirmation only came after Williams had already announced that the 27-year-old Finn was leaving for the Silver Arrows.

Bottas has agreed a one-year contract with Mercedes with the possibility for an extension, while Rosberg will stay on with Mercedes in an ambassadorial role. With Bottas only initially tied down to the seat until for 2017, the prospect of Mercedes launching a move for Ferrari’s Sebastian Vettel remains a very real possibility, with the four-time world champion out of contract at the end of the year.

"It's very exciting times for me," Bottas said. "I think it's going to take a while to understand that this is really happening.

"It's definitely another dream come true, to race in another team with such great history - especially in the recent years, which have been so impressive. I'm really proud to become a part of that and grateful to everyone at Mercedes for trusting my skills and giving me this opportunity.

"I've had a really warm welcome so far. Of course, I have a lot more people to meet and new faces to remember. But initially everything has felt very good."

As part of the deal, Mercedes executive director Toto Wollff has had to end his role as Bottas’s manager due to the conflict of interest, but the German was on hand to praise the Finn as he was presented at the team’s headquarters in Brackley.

"Sometimes in life, unexpected circumstances provide interesting opportunities," Wolff added.

"Nico's decision in December was a big surprise, and certainly a challenging situation for the team to handle. But weathering the storm makes you more resilient and we see this as another opportunity for the team to grow.

"Valtteri is a no-nonsense guy, down to earth, straightforward and very focused. Pretty Finnish, to be honest, and a great fit for us.

Hamilton's new teammate at Mercedes will be Bottas (right), who replaces Nico Rosberg (centre) (Getty)

"He has an impressive track record in the junior categories and nine podiums in F1. But now it's time for the next level, to see how he can step up to challenge for race wins and for championships.

"We know that we are already behind the curve in terms of preparations for the new season, so we've got a busy programme to get him integrated into the team. One thing is for sure: as I know Valtteri, he will give it everything."

Bottas has claimed nine podiums to date but is yet to secure his first Grand Prix victory, and he signalled his intention to stand on the top step of the podium in 2017 while helping the Silver Arrows to claim as many points as possible.

Felipe Massa comes out of retirement to replace former teammate Bottas at Williams (Getty)

His departure means that 35-year-old Massa will remain on the grid this season, despite retiring from the sport after the Abu Dhabi Grand Prix in November.

A Williams statement confirmed: “Williams Martini Racing is pleased to confirm that Felipe Massa has agreed to re-join Williams on a one-year deal, coming out of retirement to replace Valtteri Bottas who the team has released to join Mercedes for the 2017 season.”

Massa, who will partner rookie Lance Stroll, added: “Firstly, I am very happy to have an opportunity to return to Williams. I always intended to race somewhere in 2017, but Williams is a team close to my heart and I have respect for everything it is trying to achieve. Valtteri has a great opportunity, given the turn of events over the winter, and I wish him all the best at Mercedes.

“In turn, when I was offered the chance to help Williams with their 2017 Formula One campaign, it felt like the right thing to do. I certainly have not lost any of my enthusiasm for racing and I’m extremely motivated to be coming back to drive the FW40. The support from my fans over the last few weeks has been a huge boost and I'm grateful for that. I also look forward to working with Lance; I’ve known him for many years and seen his talent develop during that time, so I look forward to seeing what we can achieve together.”

F1 2016 driver ratings Show all 23 1 /23 F1 2016 driver ratings F1 2016 driver ratings Nico Rosberg – 9 out of 10 After losing two consecutive title battles to his Mercedes teammate, even Nico Rosberg appeared to doubt Nico Rosberg last February. The fact he bounced back to triumph is great testament to his character and determination. Standout drives in Azerbaijan, Italy, Singapore and Japan were reinforced by his tremendous recovery to third in Malaysia. The only negative is he still hasn’t convinced anyone that he’s more talented than Hamilton. Getty F1 2016 driver ratings Lewis Hamilton – 8 out of 10 Reliability issues and grid penalties. The story of 2016 for Lewis Hamilton, but he‘s guilty of taking his eye off the ball too. Rosberg had no right to get back into the title fight after the summer break, but Hamilton was no longer the mighty force we’ve come to expect and allowed off-the-track distractions to impact his cause. Malaysia’s engine blow-up was pivotal in the title battle and ended up with him accusing his own team of sabotage, but the dropped points in Bahrain, Azerbaijan and Singapore also cost him dearly. Getty F1 2016 driver ratings Daniel Ricciardo – 9 out of 10 After a baron 2015, it was a delight to see the Ricciardo smile back on the top step of the podium in Malaysia – and introducing the ‘shooey’ to boot. He cruelly had victory snatched away from him by his team twice in Spain and Monaco. Faced a fresh challenge when Verstappen stepped up, but more often than not kept him at bay. Getty F1 2016 driver ratings Max Verstappen – 9 out of 10 Lit up the season with his breath-taking drives through the field. Stunned the world when he won in his very first drive for Red Bull in Spain, but it will be his drive from 16th to third in the atrocious conditions in Brazil that will go down in history. Clashed with Vettel and Raikkonen and his defensive driving has been under scrutiny. But he has the talent to win multiple world championships, now he just needs the car. Red Bull may just deliver that in 2017. Getty F1 2016 driver ratings Sebastian Vettel – 7 out of 10 Seven podium finishes fell like short change from a Ferrari that was tipped to challenge Mercedes in pre-season, but the fact is that Vettel has been ringing a lot out of what has proven a really poor car. Consistently out-drove Raikkonen, and will hope to get back on top of the rostrum in 2017. Getty F1 2016 driver ratings Kimi Raikkonen – 6 out of 10 Showed signs of the old Kimi in the first half of the season with plenty of smart strategies that brought him into podium contention. Tailed off as the season wore on though, and looked to be somewhat affected by his battle with Verstappen. Getty F1 2016 driver ratings Sergio Perez – 7 out of 10 His two impressive third-place finishes came in Monaco and Azerbaijan, but it was his consistency over the second half of the season that really stood out and secured him seventh in the standings. Reeled off 10 straight top 10 finishes to consolidate his position as Force India’s No 1. Getty F1 2016 driver ratings Nico Hulkenberg – 6 out of 10 You do wonder if he will ever reach his true potential. Linked with a move to replace Raikkonen at one point, he will now start 2017 at Renault. They may be a manufacturer, but are they where the German should be at the peak of his career? Getty F1 2016 driver ratings Valterri Bottas – 6 out of 10 Kept his head as chaos unfolded around him to take an impressive podium finish in Canada, but his performances tailed off as the season wore on and he ended 2016 with a whimper, struggling to 11th in Brazil before retiring after a handful of laps in Abu Dhabi. Getty F1 2016 driver ratings Felipe Massa – 5 out of 10 Perhaps he took his eye off the ball after announcing his retirement at the end of the season, but his performances through the latter stages tended to result in either retirement or a mid-field finish. Highlight performances in Melbourne and Sochi hinted to a better farewell, though he deserved every second of his emotional send-off in Brazil. Getty F1 2016 driver ratings Fernando Alonso – 7 out of 10 The Spaniard showed his class on a number of occasions in a McLaren that is still not up to scratch. Saw off Jenson Button in the battle of the veteran world champions, and after starting his season upside-down in Melbourne in a frightening accident, he recorded two fifth-place finishes and nine points-scoring results to stand out from the rest. Getty F1 2016 driver ratings Jenson Button – 5 out of 10 A sixth place in Austria is as good as it got, but some may argue it was one year too many for JB, and they might be right. With Alonso scoring more than double the points Button managed and Stoffel Vandoorne waiting in the wings, he disappointed this season though that wasn’t through a lack of trying. Still one of the most popular figures in the paddock, he’ll be missed. Getty F1 2016 driver ratings Carlos Sainz – 7 out of 10 Enjoyed a tremendous start to the season with regular points-scoring finishes, and showed his undoubted talent with three sixth-place finishes. Sainz also demonstrated a good understanding of the Pirelli tyres as he excelled on long runs, and a place in the senior Red Bull team may not be as far off as it looks. Getty F1 2016 driver ratings Daniil Kvyat – 3 out of 10 What started at Red Bull ended with Kvyat riding a bicycle back to the paddock in Abu Dhabi. It may seem like a distant memory but Kvyat actually finished on the podium back in China in his penultimate Red Bull outing, though once he was ousted by Verstappen he managed to take just four more points throughout the season. Lucky to keep his place at Toro Rosso. Getty F1 2016 driver ratings Romain Grosjean – 6 out of 10 Looked like he could be one of the surprises of the season with the newly-formed Hass F1 team, as the American outfit scored points in their very first F1 race. The season started to become a struggle as it wore on though as the Frenchman’s car suffered repeatedly from brake issues, but he still demonstrated that he had raw pace when everything clicked. Getty F1 2016 driver ratings Esteban Gutierrez – 2 out of 10 While Grosjean impressed with 29 points, Gutierrez was nothing short of terrible this season and managed to finish the year as one of only two full-time drivers without a point. He also faced the fury of the front-runners who were less than impressed with his reactions to blue flags, and his angry reaction to being dropped by Haas was a rather damning indication of his character. Doesn’t deserve a 2017 seat at Manor. Getty F1 2016 driver ratings Kevin Magnussen – 4 out of 10 Billed as the unbeatable teammate at Renault, the Dane is leaving after just one year. Outscored Jolyon Palmer with an assured drive in Russia and also used the Renault’s strong technical aspects to score points in Singapore. Off to Haas next year, which may be a wise move for him. Getty F1 2016 driver ratings Jolyon Palmer – 4 out of 10 Turned around a difficult year to record a string of impressive drives in the second half of the season to out-perform Magnussen. History shows he gets better the longer he spends in a certain formula, but he’ll have his work cut out next year when Hulkenberg comes to town. Getty F1 2016 driver ratings Felipe Nasr – 4 out of 10 He struggled this season, but delivered the goods when it mattered most to score two crucial points for Sauber that lifted them above Manor in the Constructors’ Championship. Deserves another shot, and while his projected deal with Sauber has been held up, it should get over the line before 2017. Getty F1 2016 driver ratings Marcus Ericsson – 3 out of 10 A dismal run through the middle of the season saw Nasr fight back in their head-to-head battle, and it was his fault when the pair collided at Monaco in a moment to forget. The only other driver not to score despite competing in every grand prix. Getty F1 2016 driver ratings Pascal Wehrlein – 4 out of 10 It’s almost F1 law that the Manor should be at the back of the field, so it was a delight to see Wehrlein take tenth and claim a point in Austria. He showed signs of why Mercedes rate him so highly with a second standout performance in Bahrain. Getty F1 2016 driver ratings Esteban Ocon – 5 out of 10 Came in for the Belgium Grand Prix and instantly provided more competition for Wehrlein, and if you count their retirements, he won the inter-team battle 7-2. Has secured himself a role at Force India next year, which isn’t too shabby at all. Getty F1 2016 driver ratings Rio Haryanto – 1 out of 10 Remember him? His F1 spell lasted all of 12 races where he secured a best finish of 15th. Don’t expect him back any time soon. Getty

It was also confirmed on Monday that former Manor F1 driver and Mercedes development driver Pascal Wehrlein has agreed to drive for Sauber in 2017 where he will partner Swede Marcus Ericsson.

22-year-old Wehrlein, who replaces the departed Felipe Nasr, said: "I am very delighted at being a part of the Sauber F1 Team for the upcoming Formula One season," Wehrlein said. "It is a new challenge in a new team, and I am really excited and looking forward to this new adventure.

"Our objective is to establish ourselves in the midfield and to score points on a regular basis. That being said, I will do my best to support Sauber.

The Williams’ deputy team principal, Claire Williams, confirmed that the chance to driver for the reigning world champions was “a fantastic opportunity” for Bottas, who was presented by Mercedes shortly after the Williams announcement in a live Facebook stream.

“I’m delighted that Felipe has agreed to come out of retirement to be a part of our 2017 campaign,” Williams said in her statement. “With Valtteri having a unique opportunity to join the current Constructors’ Champions, we have been working hard to ensure that an agreement could be made with Mercedes to give Valtteri this fantastic opportunity.

“Valtteri has been part of the Williams family since 2010 and in that time has proved a huge talent, securing nine podium finishes. I would like to take this opportunity to thank him on behalf of the whole team, and wish him a successful season as he joins Mercedes.”

Massa thought he said farewell to his fans in 2016 but will return for one more year (Getty)

It was also confirmed on Monday that former Manor F1 driver and Mercedes development driver Pascal Wehrlein has agreed to drive for Sauber in 2017 where he will partner Swede Marcus Ericsson.

22-year-old Wehrlein, who replaces the departed Felipe Nasr, said: "I am very delighted at being a part of the Sauber F1 Team for the upcoming Formula One season," Wehrlein said. "It is a new challenge in a new team, and I am really excited and looking forward to this new adventure.

Wehrlein spent the 2016 season with Manor and moves to Sauber for 2017 (Getty)

"Our objective is to establish ourselves in the midfield and to score points on a regular basis. That being said, I will do my best to support Sauber.

"Now I am looking forward to meeting everyone in the team and to tackling the preparations for the 2017 season. I want to say a big thank you to Sauber for trusting in me and giving me this great chance. And surely, a huge thanks also goes to Mercedes for the support."