The two-time Supercars champion will work across GRM’s diverse programme, which includes running cars in TCR Australia, S5000 and Trans Am.
GRM also heads up the construction and development of the AF01/V8 chassis that underpins the entire S5000 category.
According to GRM, Ambrose’s role will include driver coaching, car preparation, engineering and team operations.
“Having Marcos as a part of GRM is not only fantastic for us as a team, but for the sport and the categories we are competing in,” said team owner Garry Rogers.
“We all know Marcos is one of the most respected racing drivers Australia has ever produced. You also don’t win two [Supercars] championships and race for Richard Petty in NASCAR without developing a sharp perspective on how to go motor racing.
“That’s not just driving the racecar, it’s working with commercial partners, it’s the mechanical side, it’s organising a team… right down to how you pack the transporter.
“We have a brilliant and experienced team, but we never stop learning and the input of Marcos will no doubt help to bring out the best in all of us.”
The recent link between Ambrose and GRM was established recently through Ambrose’s relationship with Owen Kelly, who races a GRM-prepared Mustang in Trans Am.
However Ambrose says his relationship with Rogers goes back a lot further than that.
“My relationship with Garry Rogers goes back to the early days of my racing career,” he said.
“Not many people probably know it, but Garry and his long-time sponsor Valvoline supported me in Formula Ford.
“Recently I have enjoyed getting involved with my good friend Owen Kelly and helping him return to motorsport in the Trans Am Series where GRM has been preparing Owen’s car between races.
“From that Garry and I chatted about helping the team where I could, both in terms of racing and the future growth of the GRM business.
“Garry and Barry [Rogers] run one of the most established race teams in the country and from what I have seen to date they have a very skilful and energetic workforce.
“I have always been passionate about winning and I also enjoy the engineering side of motorsport. Working with the team at GRM gives me a great opportunity to experience both.”
Ambrose had little involvement in motorsport for several years following his shock retirement just a handful of races into his Supercars comeback in 2015.
After several years off the radar he returned to the paddock this year through both Kelly’s Trans Am programme and a pair of impressive TV outings with Supercars Media.