Paltrow and Knowles best buddies?

Gwyneth Palthrow has struck up a close friendship with Beyoncé Knowles, after she and husband Chris Martin joined the R&B star's boyfriend Jay-Z on stage for a performance.

The Shakespear in Love actress and Knowles' partners are work colleagues and friends and introduced the two women.

Earlier this week, the pair spent hours shopping in Knightsbridge, London together, before a night of dining at Japanese eaterie Zuma and dancing at nightclub Movida.

Coldplay frontman Martin collaborated with Jay-Z on his new album Kingdom Come, and performed an untitled new song from the album on stage at the British capital's Royal Albert Hall on Wednesday night.