Mick Jagger, center, Ronnie Wood, left ,Charlie Watts, rear on drums and Keith Richards, right, of the Rolling Stones, perform on the Pyramid main stage at Glastonbury, England, June 29, 2013. (Photo by Joel Ryan/Invision/AP)

Mick Jagger is how old?

Rock’s royalty continues to answer the decades-old question: What will rock stars do when they’re older?