Rocker Robert Plant showed his support for partner Patty Griffin by duetting with the singer during her album launch in London on Thursday night (16May13).

Griffin took to the stage at the U.K. capital's Rough Trade East record store for the event in honour of her latest record American Kid - and the 200 fans in attendance were left stunned when Plant joined her.

The pair collaborated on the track Highway Song and Plant told the audience, "I'm glad to be here."