Sir Paul McCartney found performing for Barack Obama a "humbling" experience.

The former Beatles frontman - who recently sung hit tune 'Ebony and Ivory' alongside Stevie Wonder for the US president - said when he wrote the track, there was "no chance" there would ever be a black president.

Speaking at the Isle of Wight festival, he told Absolute Radio Hometime DJ Geoff Lloyd: "Me and Stevie Wonder sang 'Ebony and Ivory' and that was like the first time we'd done it live.

"It brought back memories of when I wrote it, and when we recorded it. There was no chance of having a black president. I mean, it was just the remotest thing ever, so to be there, singing it with Stevie, and two yards away from the black president, his wife and kids, it was very emotional actually. So yeah, I was humbled and grateful.

The 67-year-old iconic rocker went on to add he is a "fan" of the US leader and was honoured to perform in front of him.

He explained: "I've never met an incumbent president. I was very honoured to tell you the truth, because I'm a fan of his.

"I think he's a great president."

The 'Yellow Submarine' hitmaker closed last weekend's Isle of Wight festival with a two-hour set, performing Beatles hits such as 'Hey Jude' and 'Live and Let Die'.