The singer plays a set at KROQ's Almost Acoustic Christmas in Los Angeles...

GWEN STEFANI made a surpirse appearance at LOS ANGELES radio station KROQ’s ALMOST ACOUSTIC CHRISTMAS event last night (December 11).

The currently solo No Doubt singer turned up as the unannounced guest on a bill which featured Muse, Snow Patrol, Keane and The Music.

Shortly before 9pm Stefani took to the Universal Ampitheatre stage, backed by her L.A.M.B. Harajuka girls, for a two song set. Dressed in platform sneakers, and entering to a billboard which read simply ‘Gwen’, Stefani performed ‘Hollaback’ alongside a full band and drum line, while her husband, Bush frontman Gavin Rossdale, cheered her on from the audience.

Her brief set wrapped up with current single ‘What You Waiting For’, as thousands, including her No Doubt bandmate Tony Kanal cheered her on.

Stefani’s appearance was sandwiched between performances by Modest Mouse and Franz Ferdinand. Franz return to the UK this week for a pair of headlining dates at the Glasgow SECC. ShockWaves NME Awards Tour 2005 headliners The Killers also played a thrilling set, getting into the Christmas spirit by donning red velvet blazers as they performed hits including ‘Somebody Told Me’.

A host of celebrities turned out to catch the sold out show including Melissa Auf Der Maur and System of a Down’s Serj Tankian. KROQ’s Almost Acoustic Christmas continues tonight (December 12) with Green Day, Velvet Revolver, Sum 41 and My Chemical Romance.