Brian May says performing with Adam Lambert is a "privilege".

Adam Lambert and Brian May

Adam Lambert and Brian May

The legendary Queen guitarist has heaped praise on the 'American Idol' star - who has joined Brian, 71, and drummer Roger Taylor, 69, and fronted the band live since 2011 - as he shared a clip of the 37-year-old singer belting out 'Blue Suede Shoes' after stumbling on the video through a fan page.

He wrote on Instagram: "Jeeeeez! Just stumbled upon this stunning fragment on a fan site. Is this guy the nuts or what?!!

"We'll have the privilege of working with him again son - once we get back in the saddle mid January for an audacious long haul around the world. (sic)"

The 'We Will Rock You' hitmaker also pondered whether anyone else in the world can match Adam's vocal talents as he shared a stunning live rendition of his song 'Closer To You' from an appearance on the 'Late Late Show'.

Again posting the clip on social media, he added: "You know - I do sincerely wonder if, in the 7.7 Billion people on Planet Earth there is another voice quite like this.

"Yay! I'm having an @adamlambert Adam Lambert evening!! Thanks to a fan account @adamlamber049 - thanks!

"Wow - reeling from this totally live performance on the James Corden show. And... do you feel like you're watching a huge orchestral rock you? This stupendous sound is just a voice and a piano!!! Yeeeow. (sic)"

Earlier this year, Brian paid Adam perhaps the biggest compliment possible as he claimed the frontman could "all the stuff" late Queen frontman Freddie Mercury did "and more".

He said: "Adam can do all the stuff that Freddie did and more. It doesn't matter what you throw at Adam -- he can do it...

"He's a born exhibitionist. He's not Freddie, and he's not pretending to be him, but he has a parallel set of equipment. We treat Adam exactly the same as we treated Freddie in almost every way."