READ MORE: LGBTQ+ Pride Month 2023: Test your knowledge with our brain-teasing quizQueen's Adam Lambert Leading the lineup is American singer Adam Lambert. The former American Idol star, 41, recently released his fifth studio album and will perform in front of thousands of spectators as they descend on Trafalgar Square. He is of course best known as the modern day stand-in for Freddie Mercury on stage with Queen.