After rocking David Letterman's New York studio on Monday with a blistering rendition of Black Sabbath's classic tune 'War Pigs', last night's continuation of Dave Grohl's week long residency saw Foo Fighters flanked by Ann and Nancy Wilson of the band Heart.

The newly assembled (and very temporary) supergroup performed Heart's 1977 hit 'Kick It Out', during which the Wilson's took front and centre leaving the Foos very much in the background for the performance. Check it out above.

A trend has most certainly developed for these Foo Fighters shows all week on Letterman. What odds on Grohl's mates Krist Novoselic and Paul McCartney showing before the week is through?