Bono was reportedly rushed to hospital earlier this week after suffering from severe chest pains.
U2 frontman was holidaying in the South of France when he began experiencing heart palpitations on Wednesday.
The singer was later checked into the Princess Grace Memorial Hospital in nearby Monaco, where he was seen by a top heart specialist who advised him to get some rest.
He did not have to stay in hospital overnight, and was spotted out relaxing with friends at a Monaco nightclub the following evening.
U2 wrapped up their record-breaking ‘360’ world tour in Canada last week, after grossing around $736m (£447m) over the past two years.