For the 2017 season, Collard switched to sportscar racing, competing in the opening three events of the ADAC GT Masters as a BMW junior driver.

During the same year, Collard made his British Touring Car Championship debut at Rockingham, substituting his father Rob who was ruled out on medical advice following concussion suffered at the previous round.

[7] In 2019, the Briton entered the sprint-formatted GT World Challenge Europe together with Marvin Kirchhöfer, driving an Aston Martin Vantage AMR GT3 for R-Motorsport.

[9] Despite this success, 2020 proved to be a patchy season for Collard, who raced in individual events of the GT World Challenge Europe Endurance Cup.

The peak of his year came at the 24 Hours of Spa, where he helped Barwell Motorsport, in a lineup which included Sandy Mitchell, Leo Machitski, and Collard's father Rob, towards victory in the Pro-Am class.