Lohan duets with Ronson family

Lindsay Lohan has performed a duet with her girlfriend Samantha Ronson and the DJ's brother Mark - taking the stage at a family celebration in London.

The actress/singer attended a Jewish Bar Mitzvah ceremony for one of Ronson's relatives at a synagogue in London on Saturday.

The family went on to celebrate the occasion with a party at the Mandarin Oriental hotel, in London’s Knightsbridge.

And Lohan delighted guests by taking to the stage at the event to sing with her lover, performing the Beatles' 'With A Little Help From My Friends'.

The girls were joined by Ronson's older brother, Mark, who accompanied them on guitar.

A source tells The Sun, "It was amazing. Everybody loved it. Lindsay and Sam looked really loved up.”