Rihanna joined Sir Paul McCartney on stage at Desert Trip on Saturday night (15.10.16).
The 28-year-old singer made a surprise appearance at the six-day music festival, held at the Empire Polo Club in Indio, California, when she rocked up to perform their hit song 'FourFiveSeconds'.
The pair, who co-wrote the track with Kanye West, have both featured the single in their set lists since the single was released, but they haven't actually performed it together since the 2015 Grammy Awards.
Rihanna appeared to be having the time of her life as she walked out on stage in a pin-striped baggy suit and kicked off the catchy track while McCartney strummed the tune on his guitar.
Once the track was over, the 74-year-old Beatles legend joked that Rihanna, who at this point had headed backstage, was the youngest artist to appear at Desert Trip - which brought together music legends The Rolling Stones, Bob Dylan, Neil Young, Roger Waters and The Who on one bill.
He said with a chuckle: "We finally found someone under the age of 50!"
The 'Diamonds' hitmaker wasn't the only artist to join McCartney on stage as Young, 70, was also on hand to perform 'A Day in the Life', which was combined with the late John Lennon's 'Give Peace A Chance' and The Beatles' 'Why Don't We Do It in the Road?'
McCartney was watched by daughter Stella McCartney, his daughter with his late first wife Linda McCartney, as he performed his show which covered his entire career.
On Friday (14.10.16), The Rolling Stones and Dylan, 75, rocked the festival again with 73-year-old Sir Mick Jagger's band playing a set packed with hits such as 'Jumpin' Jack Flash', 'Get Off My Cloud' and 'Gimme Shelter'.
The six-night event - which took place over two weekends - was closed on Sunday (16.10.16) by former Pink Floyd star Waters, 73, and The Who.
At one point, Who guitarist Pete Townshend challenged the audience to match the energy levels of himself and frontman Roger Daltrey, 72.
After performing 'The Seeker', Townshend, 71, said: "Are you f***ing tired or something? Strange, we're not!"