The Supercars champion and former NASCAR star will join George Miedecke and Tim Brook in a Mustang run under the Miedecke Motor Group banner for the Easter enduro.
It's the second year running Ambrose has teamed up with the Miedeckes for the 6 Hour, although last year they didn't make the start due to teething problems with what was a brand new car built by Garry Rogers Motorsport.
This time the car has undergone significant development, with Ambrose confident last year's issues won't rear their head again.
"I am looking forward to finishing this story of the GRM Mustang that we built for the Miedeckes," Ambrose said.
"It was supposed to run last year but we had issues with the transmission and the car just wasn't ready. They have been working on it in Queensland for a while, been testing and it's ready to go.
"We'll have a shakedown at Queensland Raceway on Tuesday
"I'm really looking forward to teaming up with George and Andrew [Miedecke], we've been good friends for a long time and it should be a good weekend enjoying the car and the race.
"I've been up there at the 6 Hour and it's become one of my favourite events to visit on the crew side. It feels old school to me, private teams, working on their cars all year for the one big race.
"There's lots of speed difference between the cars, different configurations and 6 hours is the perfect length for the race."
Ambrose won't just be driving on the 6 Hour weekend, but will also join the broadcast team for the coverage on Nine and Stan Sport.
In that capacity he'll work alongside the likes of host Matt White, race callers Matt Naulty and Richard Craill, reporter Chris Stubbs and TCR regular Josh Buchan.
Greg Rust and Fabian Coulthard will be absent from the on-air crew due to family commitments.
"Marcos is a great addition to the team and the fact he is also racing in a competitive car means we'll have the best possible insight into what it takes to conquer the Mountain in the Bathurst 6 Hour," said SpeedSeries TV boss Andrew Janson.
"He's still highly current, forthright and honest in his opinions and that's why he's so good on TV. Our plan is that he will be able to jump straight out of the car and debrief with us at the same time, if not just after, he does with the team.
"It will be great access and insight for the audience.
"We're happy to add he and Josh Buchan to the team, plus some other guest callers, across the weekend. Rusty and Fabian will be back for Phillip Island and the remainder of the season, but this is also a chance to get some different voices into the mix.
"Between Stan Sport and the Nine Network we have a combined 18 hours of live broadcast from Mount Panorama, a record for the Bathurst 6 Hour. It's a huge undertaking but the team is ready to go."
