In a way, it's remarkable that their paths haven't crossed before.
Last night (May 29th) in Lisbon, though, the two took to the stage together. The Rolling Stones invited Bruce Springsteen to blast through their 1972 single 'Tumbling Dice'.
Truly a moment to treasure, fan footage almost immediately found its way online. Watch it now. (via NME)
The Rolling Stones' world tour is ongoing.