The two groups took over the G-A-Y night at U.K. hotspot Heaven, hours after an estimated 15,000 revellers took to the streets in the British capital to march in the 42nd annual Gay Pride parade.
Before their sets, the groups posed for photos together backstage and Backstreet Boy Nick Carter tweeted, "Getting ready to play club G.A.Y. In London. We are so excited to party with our gays. gay pride."
The festivities in London came just weeks after British government officials approved same-sex marriage legislation, paving the way for ceremonies to begin next spring (14).
Pop superstars Lady Gaga and Cher also performed in Gay Pride events held in New York this week (ends28Jun13).