Mawson, unbeaten since the revival of the Australian Drivers' Championship in 2021, will look to add a third Gold Star title to his name this season.
He'll do so as part of a new partnership between Team BRM, the team that guided him to his two titles, and 88Racing.
The latter has operated as a standalone team since the inaugural S5000 season but will team up with the Adelaide-based BRM outfit for this latest campaign.
Should Mawson secure a third Gold Star title he'll become just the sixth driver to do so along with John McCormack, Paul Stokell, Mark Skaife, Alfredo Costanzo and Bib Stillwell.
"It's really exciting and will be quite cool to be in new colours and representing 88Racing and continuing on with Team BRM as well for a third season," said Mawson.
"I've always loved being part of S5000, it's my favourite category I've been in and to come back is truly a blessing.
"The chance to compete for a third Australian Drivers' Championship is special. When I look back at the history books, some have done the double but becoming a three-time champion puts you in elite company.
"Mark Skaife won it three times and he was a hero of mine when I was growing up, so to have the chance to emulate that is special.
"It's a huge challenge, but an incredible opportunity for the year.
"Every year there are new drivers and competition, every year the level goes up and up and it gets harder to stay on top."
McLean, meanwhile, will debut in the V8-powered series with Versa Motorsport.
The deal comes after the Super2 regular tested a Versa-run S5000 at the Open test at The Bend last year.
It's expected that McLean will dovetail his S5000 commitments with a Super2 drive with MW Motorsport.
Versa will run three cars for the S5000 opener in Tasmania with McLean joined by Blake Purdie and Cooper Webster in the line-up.
"I’m seriously excited to run the year with Versa Motorsport in S5000," said McLean.
"I’ve known [team owner] Toby [Pope] for 10 years from back in the karting days and have been friends ever since, and to receive this opportunity from him has been a very special moment for me.
"Cooper and I both won Junior and Senior National Championships simultaneously whilst racing for the same brand back in 2016, so it’s cool to be back in the same camp with him just like old days.
"I sampled the S5000 with the team back at an evaluation at The Bend and was keen on putting a deal together straight away.
"Our pace seems strong, and in combination with the team's professionalism I think we’ll have a very solid year."
The S5000 field will also include Nic Carroll, who moves to the series from Trans Am, who joins Jordan Boys and Aaron Cameron at Garry Rogers Motorsport.
Zane Goddard, meanwhile, will contest at least the first two rounds of the season with Team BRM.
