Musician Paul McCartney's wife Nancy Shevell never left the singer's side during his recent stay in a hospital.

The musician was hit by a mystery virus Tuesday and he was admitted to St Luke's International Hospital here.

"Nancy has been brilliant and has never left his (Paul) side. Paul is getting better and better by the day," contactmusic.com quoted a source as saying.

The 71-year-old postponed a show in Seoul, South Korea due to his illness, but he is still set to continue with his US tour next month.