Pop star Kylie Minogue leaped out of a cake as a surprise for Mario Testino's 60th birthday in London on Wednesday (29Oct14).

The Australian singer joined a host of stars, including Keira Knightley, Kate Moss and Naomi Campbell, to celebrate with the famed photographer at celebrity hotspot The Chiltern Firehouse restaurant.

Wearing a bejewelled outfit, Minogue sang Happy Birthday to Testino and later posted a picture on her Instagram.com page of the moment she revealed herself from within the cake.

She captioned the image, "So... yes... I popped out of a cake to sing #HappyBirthday for @MarioTestino tonight ."

Other guests at the party included include Sienna Miller and Rita Ora.