Jay Z made an early unannounced appearance at London's Wireless Festival on Friday night (12Jul13) when he joined fellow headliner Justin Timberlake onstage for their collaboration Suit & Tie.

The rapper will headline the event at London's Olympic Park on Saturday night (13Jul13), but he showed up a day early to perform with Timberlake at the end of the singer's set, which included hits such as Cry Me a River, Senorita and Mirrors, as well as a cover of of Inxs anthem Need You Tonight.

Timberlake closed his headlining set with SexyBack after a brief performance with his pal Jay Z, while the singer/actor's wife Jessica Biel watched from the side of the stage, along with Rita Ora, Frank Ocean and Snoop Dogg - also known as Snoop Lion.

The Wireless Festival's first night also featured sets from Snoop Dogg and Ocean, as well as John Legend and Miguel.

Jay Z and Timberlake will be back onstage together at the event on Sunday (14Jul13), when they wrap up the festival as headliners Legends Of The Summer.