South African van der Linde pipped Mercedes driver Lucas Auer and Rast's Abt Audi to his first DTM crown last season, in a successful maiden campaign for the new BMW M4 GT3 and series newcomer Schubert, but the championship's future was then plunged into doubt when Gerhard Berger's ITR group sold rights for the series to rival German promoter the ADAC.
After some uncertainty, the ADAC announced it would continue to run the DTM as a sprint series for single drivers alongside its existing ADAC GT Masters platform for two driver crews, enabling DTM teams to press on with plans for 2023.
BMW Motorsport's announcement on Tuesday morning that Schubert will retain van der Linde and run newly-signed BMW factory driver Rast in all rounds aside from Zandvoort - which clashes with his McLaren Formula E commitments - coincided with the reveal that Project1 will enter the series as a BMW GT3 customer for the first time after running its products in the GT4-based DTM Trophy.
The long-time Porsche squad, a Le Mans 24 Hours class-winner in the GTE Am division in 2019 who will also contest the World Endurance Championship this season, has signed two-time DTM champion Marco Wittmann as its first driver.
The driver of a second car will be selected at a later date, according to a statement, "in close consultation between the team, BMW M Motorsport and the ADAC".
"It’s fantastic that I have the opportunity to defend the first title of my career with the Schubert team," said van der Linde.
"Everyone says it is harder to defend a title than it is to win one for the first time. I’m excited to see how it goes.
"The new DTM will be a big challenge for everyone. Whoever can adapt to the new conditions the quickest will do well.
"I’m trusting in the abilities of my team, who will no doubt be even stronger than last year.
"It’s fantastic to be driving with a major champion like Rene Rast. I have no doubt that we will be able to push each other."
Multiple GT World Challenge Europe Sprint Cup champion Dries Vanthoor will replace Rast, who departed the Audi fold at the conclusion of last season, at Zandvoort.
BMW Motorsport boss Andreas Roos said: "We are pleased to have the opportunity to defend our titles with Schubert Motorsport and Sheldon van der Linde. The team and drivers did an outstanding job as the ones to beat at the 2022 season finale.
"Rene Rast is a great signing for the Schubert team’s second BMW M4 GT3. Obviously it is a shame that he will miss one of the race weekends due to a clash with Formula E, but we have confidence in Rene’s class and believe that he will still be one of the main players in the championship.
"Project 1 is a very exciting new BMW M Motorsport DTM team. The journey the team’s professionalism has taken them on in recent years has impressed us all.
"We are intrigued and are really looking forward to this joint project. In our opinion, a champion like Marco Wittmann is the perfect choice as a team leader."
Wittmann, who won the final round of last season with Walkenhorst Motorsport, added: "I am highly motivated and very much looking forward to taking on the new challenge with Project 1.
"Naturally, being successful as a new team will require coming together quickly, but everyone who knows me is aware that I am always hungry for success and have brought home top results early on with new teams in the past.
"The hard work starts now, so that if everything goes according to plan I can start the new season the same way I ended the last one – with a win."
The trio are the first confirmed drivers for the 2023 season, which gets underway at Oschersleben on 26-28 May.
Porsche has announced that 2022 race winners Thomas Preining and Dennis Olsen will return this season, but has yet to reveal the teams they will be driving for.
Meanwhile the AF Corse-run Red Bull Ferrari squad will not be returning following the switch to the ADAC platform.
