Adam Lambert is joining rock band Queen for one concert this summer, at Sonisphere 2012.
The former American Idol singer tweeted: "As many suspected, I can finally confirm: I have been invited by Queen to sing one very special concert! Sonisphere at Knebworth July 7th!"
Adam had previously tried to play down his comments that he planned to perform a tribute to the late Freddie Mercury, the band's lead singer.
But he added: "Sorry to be coy about the details the past few weeks, but I made a promise to keep it under wraps as best I could. Gonna be a surreal night!"
Adam, 30, has sung with Queen before. In 2009 he performed We Are the Champions on the US reality show that made his name and then last November he sang an eight-minute set at the MTV Europe Awards to celebrate Queen's Global Icon Award.
Freddie Mercury's final concert with Queen also took place at Knebworth, in August 1986. He died in 1991.
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