Lady Gaga duets with Yoko Ono at US concert

The concert took place at the Orpheum theatre

Pop star Lady Gaga joined Yoko Ono on stage to perform two songs at the end of a three-hour gig from the Plastic Ono Band in Los Angeles.

The Poker Face singer, 24, paid tribute to Ono, 77: "Thanks for being so brilliant and such an inspiration to so many women."

The pair ended the evening lying next to each other on the top of a grand piano.

Ono's late husband John Lennon founded the Plastic Ono Band in 1969.

Their son Sean Lennon is now the musical director.

The concert comes ahead of a weekend of celebrations planned for Saturday 9 October, which would have been John Lennon's 70th birthday.

Ono is planning a series of peace-promoting events in Iceland that day and will light the Imagine Peace Tower, as she does every year on that day.

The tower was unveiled in 2007 near Reykjavik as a memorial to John Lennon from his wife.

It is inscribed with the words: "I dedicate this light tower to John Lennon, my love for you is forever, Yoko Ono."

That will be followed by the Plastic Ono Band playing a special concert.

A special edition guitar is also being created to tie-in with Saturday's celebrations, at the request of Ono.

The Gibson guitar factory in Montana will release a limited number of J-160Es, the model of guitar Lennon played.