The former Beatles legend is on tour with a new band, despite reaching 60 years of age, and shows no signs of slowing down.
He says, "After a tough few years I feel like I'm back in the land of the living."
And the YESTERDAY hitmaker says Heather is the one to thank for his rejuvenation.
He adds, "She is a fantastic woman with a great sense of humour and, let's face it, she's not hard to look at.
"She works her butt off for her land mines charity and she doesn't get a penny for it. People think I do a good job but it's nothing compared to her. She gives people their lives back. I've seen it."