Liverpool have confirmed that Adam Lallana has signed a long-term contract at the club.

A source told ESPN FC that the midfielder has put pen to paper on an improved three-year deal, which starts this summer, and has the option of a further 12 months.

Lallana's weekly wage will now be in the region of £110,000-a-week, the source added.

The new contract and increase in earnings is a reward for Lallana's excellent performances in a central-midfield role this season.

✍ #LFC are delighted to announce Adam Lallana has signed a new long-term contract with the club! Read more: https://t.co/UOXs8ujaGh pic.twitter.com/W8H82bNJZi - Liverpool FC (@LFC) February 22, 2017

Speaking about his new contract, Lallana told the club's official website: "I'm very proud and feel quite humbled by the show of faith from the club and the manager in particular.

"Signing for a club like Liverpool is obviously a big thing - but to re-sign shows you've obviously contributed enough that the people who make the decisions want you to stay longer.

"This is a really good place to be at the moment and, for a player who wants to be part of something special, I can't think of a better club to commit your future to.

"We have a brilliant squad of players who are only going to get better the longer we are together. We have a world-class manager and coaching staff.

"And because it's Liverpool there is that added X-factor of the supporters and what success would mean to them when we achieve it here. I'm just delighted that I'm going to be part of it for even longer."

Lallana has been in fine form this season. Jan Kruger/Getty Images

Manager Jurgen Klopp added that the midfielder's best years are still ahead of him.

"This is fantastic news for the club because Adam is a great player and an even better person," he said. "I am so pleased that we will spend more time together now and have this common future with LFC trying to be successful here.

"Adam is a natural leader and is so, so important within our team and also in the dressing room. Maybe on the outside his leadership is not seen as much as we see it each and every day at Melwood in everything he does.

"What I think is most exciting about this news is that this player is only just arriving at his peak. He has his very best years ahead of him and they will be at LFC. He is in fantastic shape and his passion for football is as high as I have seen in a player - you not only see that out on the pitch in matches, but also in training here at Melwood.

"People talk about his progression and his improvement in the last 18 months, but for me he has shown this quality since my first day at Liverpool.

"He has a world-class attitude to go with outstanding ability: that's not a bad combination!

"Our younger players will now be able to benefit from watching, listening and learning from him for an even longer period because he sets the perfect example each and every day."

The former Southampton captain has made 27 appearances for Jurgen Klopp's side so far this term, scoring seven goals -- equalling his best goalscoring tally for the club.