The growing list of special guests that have been welcomed to the stage for the Rolling Stones' '50 and Counting' tour added another big name on Saturday (May 11), when the band was joined by multiplatinum pop star Katy Perry for a special duet rendition of 'Beast of Burden.'

This isn't the first time that the song, originally a Top 10 single from the group's 1978 'Some Girls' album, has been covered in a duet setting; in fact, Bette Midler scored a minor hit with her 1983 version, which flipped the song by putting her in front and featuring Mick Jagger on guest vocals.

The band broke the news about Perry's appearance via Twitter, telling followers a few hours before the show with a tweet that sparked a mini-love fest, with Perry responding that she was "much obliged & quite honored" and a clearly enthused Jagger adding that he was "really looking forward to duetting with Katy tonight." After the number, grammar went completely out the window for Perry, who told followers, "Yes, I just did gyrated on Mick Jagger. WHAT?!"

Perry's guest spot (which is embedded above for your viewing pleasure) puts her in some fairly elite company during the latest tour; as Rolling Stone points out, the band's recent shows have incorporated a list of artists that includes John Fogerty, Bonnie Raitt, Tom Waits, and Gwen Stefani.