Taylor Swift was joined on stage by Sam Smith at London's O2 Arena this weekend.

The blonde beauty invited the Brits Critics' Choice Award winner to team up with her last night (02.02.14) in England's capital, where she has a set of dates lined up as part of her RED tour.

The pair performed 'Money on My Mind' - which is from Sam's upcoming album 'In The Lonely Hour' - and the song has become a ''favourite'' for Taylor.

She wrote on Twitter: ''Tonight at the O2, @samsmithworld sang my new favorite song ''Money On My Mind'' and smashed it! You need this song/artist in your life! (sic)''

Sam thanked the ''gorgeous'' star and was thrilled to have been given the exciting opportunity.

He wrote on Twitter: ''Thank you so much to the gorgeous @taylorswift13 for singing 'money on my mind' with me tonight at the O2!! (sic)''

Taylor kicked off her five-night residency in London on February 1 where she was joined by Ed Sheeran for a performance of 'Lego House' and is due to head to Berlin on February 7.