The 'My God is the Sun' hitmakers were honoured to watch the piano legend lend his piano skills to the track 'Fairweather Friends' on their latest album '...Like Clockwork', and admit they were in awe of the star while he was playing.
Guitarist Troy Van Leeuwen exclusively told BANG Showbiz: ''We invited him to play the song live with us. He learned the song in a pretty ridiculously short amount of time, so that was cool to watch him sort it out.
''I remember he was like, 'These f***ing guitar players, with your f***ing keys.' Because it's in a different key for piano, so to watch him adapt to that situation after never really meeting us was really cool.''
Bassist Michael Shuman added: ''It was really good to watch him figure it out pretty f***ing quickly and I was just like, 'Wow, he's a pro. He's been doing this for a long time and he knows exactly what he's doing.'
''We did it all live together, all six of us, it was awesome.''
The rock outfit - also including frontman Josh Homme, drummer Jon Theodore and keyboard player Dean Fertita - became good friends with the 'Rocket Man' hitmaker following the collaboration, and he spent an extra two hours discussing the music industry with them afterwards.
Troy said: ''Usually he would just show up and play on the ballad. He was like, 'Do you boys have a ballad?' And we were like, 'Nope!' But he liked it so much he came back and sang vocals, too. It was really great.
''He's a straight down to business guy. We did end up talking about music for about an hour-an-a-half but he had to go somewhere else. We became mates after the song.''
The band's critically-acclaimed new album '...Like Clockwork' topped the Billboard 200 chart in their native US as well as hitting the number one spot in Australia, Portugal and Ireland and Top 10 in 12 more countries.