Queen says Adam Lambert will be a "great Interpreter" of Freddie Mercury's songs at Sonisphere.

The "We Will Rock You" group confirmed on Monday they will headline the rock festival in July, with former American Idol contestant Adam taking the place of late frontman Freddie - who passed away in 1991 - and guitarist Brian May is sure he can step up to the challenge.

"I think all the vibes will be good. And I'm, sure that if Freddie was around, or if he is around then he'll appreciate what we're doing, because its interpreting those songs and those songs should live. A lot of those songs are Freddie's and you've got a great interpreter there in Adam. It will be challenging - my God, it will be challenging, but you've got to set yourself big hurdles to get over really, that's what life is about," he told BANG Showbiz, speaking at Tuesday night's BRIT Awards.

Queen have previously performed with Adam on the final of American Idol in 2009, and again last year at the MTV European Music Awards, where they received the Global Icon trophy. This summer's show is bound to be poignant as Queen played their last ever show with Freddie in 1986 at the same ground in Knebworth as Sonisphere takes place.

"We don't know how we'll feel until we play - really it's a big challenge for us. It's come around in a complete circle. I do remember the sound being absolutely brilliant on the day we played all those years ago on Freddie's last ever show with us and we're hoping we can come somewhere close to that with Adam Lambert who is a phenomenal singer and absolutely amazing talent," said drummer Roger Taylor - the other remaining member of the original group.

Tickets for the show are on sale from nine am on Thursday at www.sonisphere.co.uk.