The 39-year-old Scot is one of the most successful drivers in the championship's history.
He first claimed the overall British GT3 title in 2015 with Beechdean and followed up with success for TF Sport in 2016 and 2019. He also notched a further crown in 2018 with Optimum Motorsport.
The Aston Martin factory driver jointly holds the record for the most overall wins in the series and will partner Giacomo Petrobelli for Blackthorn’s first full-time campaign in the championship this term.
The squad was founded in 2022 by Dan Jeal and David McDonald and has become an Aston Martin partner team. Blackthorn made its British GT debut last season in a one-off outing at the Silverstone three-hour event with Claude Bovet partnering McDonald.
“I’ve never worked with them before but I was out with them last week in Portimao and already it’s a nice relationship,” said Adam, who raced with James Cottingham in a 2 Seas Mercedes-AMG last year, taking three wins and emerging as championship contenders.
“They seem like a good bunch of people and they have big aspirations to do a good job. I’m excited to come back.
“I’ve always enjoyed racing with new teams. This will be my fifth team in British GT and in the past I’ve always done a reasonably good job.
“I’ve known Giacomo for a good few years now. I’ve worked with him but I’ve never actually raced with him. He has done a little bit in the championship but it’s nice he’s doing a full programme.”
Italian Petrobelli is a former regular in the Blancpain Endurance Series, taking third in the 2012 Pro-Am rankings in a Ferrari.
He previously made two appearances in British GT, both aboard a TF Sport-run Vantage at Silverstone in 2020 and 2021.
“I am really looking forward to being back in British GT with Aston Martin and Blackthorn, and to have Jonny as a team-mate,” said Petrobelli.
“It looks like the championship has become even more competitive since I last drove in it, with lots of fast Ams and factory drivers, but we are hoping to be fighting at the front.”
Blackthorn will also run a second Vantage for Silver-Am pairing Josh Rowledge and Matt Topham.
Rowledge, the 2022 Ginetta Junior champion, made his British GT debut last season in a DTO Motorsport-run McLaren Artura GT4, in which he took four podiums.
Topham, meanwhile, finished as runner-up in the GT4 class in 2022 alongside Darren Turner and also made three GT3 appearances with Enduro Motorsport last term in both the older Vantage and McLaren 720S.
