Lady Gaga has assured fans that Tony Bennett is “ok” after he cancelled their concert.

The 88-year-old singer had been due to take to the stage at London’s Royal Albert hall on Tuesday night alongside Gaga, with whom he collaborated on recent album Cheek to Cheek.

However, after falling ill with the flu, Tony was forced to pull out of the gig.

After the news broke, Tony took to Twitter to dismiss claims he had suffered a heart attack.

“Sorry to not be singing in London tonight,” he tweeted. “I love my fans in the UK and appreciate all the well wishes to get over this flu quickly.”

Gaga also posted her own reassurances to fans. The 29-year-old singer has a close relationship with Grammy-award winning Tony, and insisted the show will be rescheduled.

“Hey everybody! Don't worry about Tony, he's ok!” she wrote. “That's just showbiz sometimes. We'll catch u next time, we got you!”

Tony’s spokesperson expanded on the news, but did not confirm whether or not the show will be rescheduled.

“Live Nation has confirmed that the performance by Tony Bennett and Lady Gaga previously scheduled for this evening at the Royal Albert Hall is not taking place,” the publicist said in a statement.

“Unfortunately, Tony Bennett has come down with a flu virus which has prevented him from performing the second of two sold-out shows in London.

“Ticket holders are instructed to retain their tickets to this event pending more information.

“Fans who have purchased tickets online will be notified via the ticket outlets as soon as additional information is available.”