Sydney Sixers and Perth Scorchers have named three new overseas signings, with West Indies T20 captain Carlos Brathwaite and Englishmen Joe Denly and Tim Bresnan to all feature in the back half of the KFC Big Bash League.

Brathwaite and Denly come into the Sixers' squad as replacements for England one-day players Sam Billings and Jason Roy after Monday night's clash against the Hobart Hurricanes.

Bresnan will arrive in Australia this week and will replace England allrounder David Willey, with the 32-year-old available for selection for the Scorchers' match against Sydney Thunder on January 11.

Rooted to seventh on the ladder and winless after five games, the Greg Shipperd-coached Sixers must win the rest of their games to have any hope of making the finals.

Braithwaite's entertaining wicket celebration

"Carlos' all-round skills will be welcomed, his power hitting and wily medium pace, and dynamic fielding all go to make him a precious resource in this format," Shipperd said.

Brathwaite will join the Sixers' directly from the West Indies' tour of New Zealand, after he played for the Sydney Thunder in last year's tournament.

A big-hitting middle-order batsman, the 29-year-old has a strike rate of 151.13 in domestic T20 cricket and made his name when he struck 34 from 10 balls to win the West Indies the World T20 final in 2016.

The West Indies needed 19 to win off the final over of that match before Brathwaite blasted four consecutive sixes off England's Ben Stokes to secure the silverware.

Brathwaite leads Windies to World T20 title

Brathwaite has played 25 T20 International matches and 101 T20 domestic games and will add some much-needed batting and bowling firepower to the Sixers line-up.

"We are very excited to have Carlos join the Sixers family," Sixers general manager Dom Remond said.

"He is a world class T20 player and a fabulous entertainer. We are looking forward to him adding the wow factor for our Members and fans at the SCG for the Sydney Smash."

Brathwaite and fellow international replacement Joe Denly will be available for their match against the Thunder at the SCG on Saturday, 13 January.

Denly has been signed as the replacement for Jason Roy, who will depart the Sixers after the match in Hobart.

The 31-year-old, who plays for Kent in the ECB's County cricket competition, is an opening batsman who has played five T20 Internationals for England and 162 T20's at the domestic level.

In 2017, he was the top run-scorer in England's domestic T20 competition and holds the top T20 individual score of 127, as well as scoring over 1,800 runs at all levels of County cricket and taking home the Kent Player of the Year and Batsman of the Year awards.

"Joe has enjoyed a great past two T20 competitions as a leading run scorer in the English domestic competition and more recently a successful season in the Bangladesh league," Shipperd said.

"We will be looking forward to his introduction as one of our top order batsman who can also bowl leg spin.

"Joe also a strong reputation as a fieldsman and last season played here in Sydney so he understands our conditions and we wish him every success as we search for a strong finish in our remaining matches."

Denly has spent four summers playing Premier Cricket in Sydney with Sydney Cricket Club.

Bresnan returns to the Scorchers after playing in their title-winning side last summer and is set to provide some pace-bowling reinforcement with Willey, Jhye Richardson and Andrew Tye all involved in the Gillette ODI series.

"The trend of the Scorchers getting players back who have been with us before has worked well in the past," coach Justin Langer said.

"Tim was with us last year he's a great professional and an outstanding bloke, when I told the players everyone was really excited because he's the consummate team man."

"It was a short turn around for Tim to get to Australia but he was happy to do it because I think he had such a great time last year. It was a bit harder to convince Hannah, his wife after just having their third child but it was great to get him back on board.

"We've said all along we would only get one international player this BBL, but after injuries to Nathan Coulter-Nile and Jason Behrendorff ruled them out of the season and then the exciting news that Jhye Richardson and AJ Tye will be leaving us for the ODI's meant we had to look at another option.

"We've known our bowling stocks could potentially take a hit, we've got some great local talent that we're confident in, but we just need to maintain the depth of our fast bowling.

"Having someone like Tim come into the Scorchers squad will be a welcome lift both on the field and off."