Kesha joins Renee Rapp at Coachella for rendition of 2009 anthem Tik Tok

Kesha joins Renee Rapp at Coachella for rendition of Tik Tok (Andrew Milligan/PA)

Pop star Kesha joined Renee Rapp on stage in a surprise performance at Coachella.

Mean Girls actress and singer Rapp brought on 37-year-old Kesha to duet on her 2009 debut track Tik Tok at the Outdoor Stage on the final day of the Californian music festival.