The Briton has signed for Nathan Freke's squad as the 2023 British GT3 title-winning outfit enters the championship for the first time in the Bronze Cup.
BMW Motorsport factory driver Dennis, who races an Andretti-Porsche in Formula E, will share the M4 GT3 with reigning British GT champion Darren Leung and compatriot Toby Sowery.
It marks a return to the championship for Dennis, who contested two rounds in 2021 with a Walkenhorst-run M6 GT3 and previously spent the 2018-19 seasons campaigning R-Motorsport Aston Martins.
He notably won the Silverstone Endurance Cup round in 2018 alongside Nicki Thiim and Mathieu Vaxiviere, and also has two-second places to his name at Barcelona in 2017 and 2019, the first of those aboard a WRT-run Audi.
"It’s always great to continue in GT3 racing with BMW and to be racing with the British GT champions, I’m confident we can fight for class wins,” said Dennis.
"GTWC has some of the best GT teams and drivers out there so it will be a good challenge for us.
"Testing has been positive so far so I think we can go into the first race in Paul Ricard with high confidence."
Sowery, an LMP2 class winner in the Asian Le Mans Series earlier this year, made his last Endurance Cup outing aboard a Lamborghini in 2018.
The IMSA regular said "it will be a great challenge for me to acclimatise to GT racing again".
Leung meanwhile will enter the Sprint Cup with his regular 2023 co-driver Dan Harper as he combines GTWCE with a full season in the World Endurance Championship's LMGT3 class with WRT.
"My objectives are clear-cut and purposeful," said Leung.
"Firstly, I aim to narrow the performance gap to my experienced teammates, using their expertise as a benchmark for my development.
"Secondly, it’s about capitalising on the results available to us through strong teamwork, not focusing on uncontrollables and maximising every opportunity available to us."
The five-round Endurance Cup begins with a 500km race at Paul Ricard on 7 April, before the blue ribband Spa 24 Hours on 29-30 June is followed by three-hour races at the Nurburgring (28 July) and Monza (22 September).
A new six-hour race at the Jeddah Corniche Circuit in Saudi Arabia will conclude the campaign on 23 November.
