Los Angeles (AFP) - Desert Trip, the festival of renowned 1960s rockers, in its second weekend featured a star of the young generation - Rihanna.

The pop star joined former Beatle Paul McCartney on stage on Saturday night (Oct 15) in the California desert to join in FourFiveSeconds, the song he released last year with her and rapper Kanye West.

"We finally found someone under 50," McCartney said as he invited Rihanna, 28, on stage, according to postings on social media.

The inaugural Desert Trip is taking place over two consecutive weekends with line-ups of rock legends who have never played together before.

Besides McCartney, the festival features the Rolling Stones, Neil Young, The Who, Roger Waters and Bob Dylan - who in between the weekends won the Nobel Prize for Literature.

The festival was put together by the promoters of Coachella, which takes place each April at the same site and is famous for surprise guests.

With its all-star line-up and premium prices for seats and amenities, Desert Trip - nicknamed "Oldchella" by both detractors and fans - is expected to be the highest-grossing festival of all time.