Robbie Williams took to the stage over the weekend to perform at the Pinkpop music festival in the Netherlands.
And while there, the former member of the pop group Take That energetically sang three songs for the adoring crowd.
But when the band began playing the fourth song of his set - the 2002 song Monsoon - Robbie was clearly out of breath and quickly asked them to stop playing.
"No, stop, stop," he said.
The 49-year-old then placed his hands on his knees, crouched forward and took a few deep breaths.
WATCH: Robbie Williams meets his children after three weeks quarantine (Article continues after video)
In April 2020, the singer was certain he had contracted COVID-19 while quarantining in Australia.
"I could feel my body was getting lethargic and tired and heavy and I convinced myself I'd got coronavirus. I never normally do it but I got down on my knees and prayed. I thought about my wife and family," Robbie told The Sun at the time.
Then in January 2021, Robbie tested positive for COVID while on holiday in St Barts with his wife Ayda Field and their four children, Theodora, Charlton, Coco and Beau.
Currently, the World Health Organisation (WHO) estimates that 10-20% of people who have contracted COVID may suffer from long COVID, and states that long COVID "can affect anyone exposed to SARS-CoV-2, regardless of age or severity of original symptoms."