Graham Nash is still desperate to collaborate with Sir Paul McCartney

He told The Times newspaper: "I've sung with my heroes the Everly Brothers and played to half a million people at Woodstock.

"But one thing I'd still love to do is sing two-part harmony on Yesterday with Paul McCartney.

"I hope he'll see this as an invitation."

1965 classic Yesterday was on the Help! album, and effectively acted as Fab Four's first solo performance, featuring Macca on vocals and acoustic guitar, with a string quartet.

Meanwhile, Graham revealed he is still in contact with ex Joni Mitchell, having met the Big Yellow Taxi singer through bandmate David Crosby.

He said: "Joni Mitchell - Joan - was a friend of David's.

"The first time we met, she took me back to her hotel and played me the most beautiful songs I'd ever heard, including Chelsea Morning, Little Green and Both Sides, Now.

"I've always been attracted to beautiful, intelligent women and I immediately fell in love. We were together just over two years and I've sent her flowers on her birthday ever since."

Graham took the opportunity to reflect on the best advice he's ever head, revealing how his mother urged him to always "follow [his] heart".

He recalled: "My mother told me always to follow my heart, that my heart knows what's good and what's bad. I've followed that advice all my life."

Indeed, his advice to other people would be to "be yourself", and "realise life is short and savour every moment".

Despite acknowledging the fleeting passage of time, Graham admitted he has some regrets as he approaches his 84th birthday in February.

He said: "If I'd known I was going to live this long, I'd have taken better care of my health, stopped eating meat sooner and curbed my sugar intake."