Willow Smith joined her "big brother" Justin Bieber on stage at the Staples Center in Los Angeles last night in a surprise appearance during his sold-out show where the Biebs brought Will and Jada's youngest out to perform her hit, "Whip My Hair".

The two precocious youngsters then got down and taught the audience how to "Dougie".

Willow wasn't the only celebrity to surprise the crowd last night. Her real brother Jaden and Justin's mentor Usher also wowed the crowd.

After the show, Bieber tweeted, "LA TONIGHT WAS CRAZY!!!! USHER, JADEN, SEAN, and even my lil sis WILLOW SMITH!!!! WE SHUT LA DOWN!!!!!!!! LOVE YALL."

We're sure the feeling is mutual!