It's hard replacing a legend, but Queen have found varying degrees of success with both Bad Company frontman Paul Rodgers and more recently former American Idol champ Adam Lambert. But did you know there was another possibility for the group at one time? Pop star Robbie Williams, while chatting with SiriusXM, revealed he was asked about joining the band shortly after collaborating with Queen on an updated version of "We Are the Champions" back in 2001.

"It was amazing. It was absolutely amazing," Williams said of the 2001 session which saw them paired for a collaboration to appear in the Heath Ledger film A Knight's Tale. "I'm in the recording booth with Roger and Brian from the band, and we re-recorded 'We Are the Champions.' And I got to do the backing vocals with them, and how intricate they were, those backing vocals, and how many parts it took to get that sound. And to be in the room with real history, like proper history, just felt absolutely incredible."

Williams was then asked if the collaboration then went beyond that with an invite to join the group. "Yeah, there was, yeah. They asked me to do it," stated Williams, adding, "Even though I'm very confident here on the microphone, I have suffered with incredibly low self-esteem. And I just thought I'd save them the audacity of me even trying to step on a stage and be in the same echelon as Freddie Mercury, 'cause he, to me, is angelic — he's God-like. It was just too scary."

The singer then said in a non-serious manner, "Plus I was doing stadiums myself at the time. Didn't want to have to split it three ways."

When asked if he had any regrets, Williams said he felt Queen got it right with Lambert. "Adam Lambert, if he wasn't such a lovely person which he is, I would just be terrified of him because of his pure talent. His voice is absolutely incredible," said the singer.

See Williams speaking with SiriusXM and revisit his collaboration with Queen below. Williams, who rose to fame in the U.K. pop group Take That and eventually branched out to a solo career, most recently released last year's holiday themed The Christmas Present album. Queen + Adam Lambert are currently on a break from the road, but will start up again in late May. Dates can be found here.

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