Robbie Williams believes he battled coronavirus while holed up in an Airbnb down the road from his family's mansion in Los Angeles.
The former Take That star, 46, felt "lethargic, tired and heavy" as he kept his distance from wife Ayda Field, 40, and their four children, in the temporary accommodation.
"I was in quarantine in an Airbnb down the road from my family and started worrying about food, about my medication running out, about Beau and my family, and was just very fearful for a couple of days," the Angels singer told Britain's The Sun newspaper.
"Then I could feel my body was getting lethargic and tired and heavy and I convinced myself I'd got coronavirus."
Robbie said his symptoms quickly disappeared, however he still kept his distance from his young family for three weeks before returning home.
While the star feels "lucky" to have recovered from the illness, but has still been struggling mentally with isolation, adding: "The mental struggle has been the hardest bit about isolation, making sure we don't slip into our own dark holes."
Robbie has spoken openly in the past about his battles with depression, and credited his family for pulling him through "hideous" dark times and giving him "purpose" again.
The pop star and his actress and TV presenter wife welcomed their fourth child, son Beau, via surrogate in February.
Robbie and Ayda are also parents to daughters Teddy, seven, 17-month-old Colette Josephine, aka Coco, and son Charlton, five.