The Kings of Leon star and his bandmates were performing in Brixton in 2004 when the legendary Rolling Stones rocker appeared at the show and Caleb admits it was very "surreal".
He said: "It was very distracting because we were playing the show and there were a few empty seats up top; and then before you know it, it's Mick sitting there and banging his arms on the balcony and dancing. We were all looking at each other like, 'Holy c***, this is very surreal.' I started shaking my hips a little more. Yep, I definitely did some dancing that I hadn't done before."
And Caleb also revealed he has penned some of his most famous lyrics on bar napkins, after him and his friend perfected their arts by travelling to different locations and writing and drawing their ideas.
Speaking about his friend, he told BBC Music: "He and I used to go to random bars, all over the world. Wherever we were, if we had a day off, we'd put our finger on a map and go, 'Alright, we're going to go to this little dive bar'. And we would sit there and get some bar napkins. I would write poetry and he would draw pictures. And we would trade 'em off to each other and say, 'Alright, whichever one of us is going to be famous first, you own my lyrics - and likewise I own your art.' ... I mean, I open books and I have bar napkins from all over the world. Some of the poems are not as great, and that will let you know how boozy that night was. But every now and then, there's a clear little picture that I'm painting - and you don't remember exactly when you wrote it, or how you wrote it, but it can definitely make you proud."