Keith Richards says the Rolling Stones breathed a ''sigh to relief'' when they finally got back in the studio together.
The band celebrate their 50th anniversary this year with a greatest hits album, 'GRRR!', featuring two new songs, as well as four concerts in the UK and US. It is their first time working together since the 'A Bigger Bang' tour ended in 2007.
Keith told BBC Radio 6 Music: ''We needed some time off. What I've noticed with this band this year, rehearsing over the last few months, and putting together 'Doom and Gloom' and a couple of other tracks, is that there's almost a sigh of relief to get back to work.''
''This is what we do. The energy is certainly there. It's almost like, open the cage and let the tiger out. This is bottled up energy ready to go. That's the way I'm feeling about it and I think the rest of the band, too.''
He said: ''Charlie Watts is amazing. I don't know how I spent five years without playing with him. When I get to play with Charlie - this is my juice, man. This is my stuff. We're basically like a bunch of kids, 'Let us out, let's go'.''
The Rolling Stones' greatest hits album, 'GRRR!', is out now.