He’s currently recovering after being struck with a mystery virus that forced him to withdraw from his tour of Asia. 

Stepping out in London, where he’s been resting after flying back from Tokyo on Monday, Sir Paul McCartney looked pale as he gingerly took a stroll in the rain. 

The 71-year-old Beatles legend was accompanied by third wife Nancy Shevall, and the New Yorker was arm in arm with her husband while he held an umbrella above their heads.

The musician sported a casual hooded top and baggy trousers as he ventured out on a miserable day, while supportive Nancy was equally low key in a waterproof jacket, leggings and trainers. 

McCartney was hit by the mystery bug on May 16 - just one day after he landed in Japan ahead of his Out There tour. 

He called off the sold-out Japan tour, much to the disappointment of fans - some of whom had paid 100,000 yen ($980) to see him. 

McCartney was also scheduled to perform at a Seoul stadium on May 28. It would have been his first concert in South Korea. 

Speaking after cancelling last week, he said: 'Unfortunately my condition has not improved overnight. I was really hoping that I'd be feeling better today. I'm so disappointed and sorry to be letting my fans down.'