After Alice Cooper teased people all day Sunday (June 26) on Twitter about having a surprise guest guitarist at a concert in London, that guest turned out to be none other than actor Johnny Depp.

The 'Pirates of the Caribbean' star joined Alice Cooper for performances of two signature hits -- 'I'm Eighteen' and 'Schools Out' -- at the intimate club show. The rendition of 'School's Out' also featured a portion of Pink Floyd's 'Another Brick in the Wall.' (Interestingly, those songs ranked Nos. 1 and 2, respectively, on our list of the Top 10 School Songs That Rock.)

Dressed in a newsboy cap and glasses, Depp held his own alongside Alice Cooper and his band, looking very much like an accomplished musician. After Depp's appearance, Cooper quipped, "I think we can use another guitar player, if this whole movie thing doesn't work out, call us."

Cooper will share the screen with Depp in a new Tim Burton movie, 'Dark Shadows,' which comes out in May 2012.

Depp has been playing guitar his whole life, and was even in the band P with Butthole Surfers singer Gibby Haynes. They were playing a 1993 gig, with Flea serving as their bassist, at Los Angeles' Viper Room the night actor River Phoenix died outside the venue.

Watch Alice Cooper and Johnny Depp Perform 'I'm Eighteen'