James Blunt and Paris Hilton duet

James Blunt sang the classic from Grease, Summer Lovin', with his ex-girlfriend, Paris Hilton.

The British singer was joined by the heiress on stage during the party for swimsuit designer Diana Jenkins last Saturday in Malibu.

The new version of the song had people singing and dancing.  Blunt and Hilton never confirmed their former relationship, but were seen kissing at many clubs.

Blunt is presently dating German model Tatiana Patitz, and left the party with her at the end of the night.