Stephen Merchant found out he was allergic to his own FLAT.
The TV funnyman was baffled that he only ever felt unwell while at home.
He brought in allergy exorcists into his pad after it went on for two years.
READ MORE: Snack-obsessed couple turn wedding into celebration of CRISPS with giant wall of 200 bags
Merchant was left with streaming eyes and couldn’t stop sneezing.
The Office co-writer also went to see a psychiatrist, as reported on What’s The Jam.
Merchant, 49, of Bristol eventually discovered it was his old mattress causing the problem.
He said: “I was allergic to my flat.
“Couldn’t figure out what the problem was.
“But I did a lot in the next couple of years to try and not just have eyes streaming, sneezing, every time I entered my flat.
“Honestly, it was brutal. I’d go away on holiday, I’d come back and within an hour I’d be sneezing, my eyes would be streaming.
“Hoovers, they were spotlessly clean, the whole house, I had allergy people come round to do tests on whether there was too much dust.
“Allergy exorcists, they couldn’t find anything.
“I thought maybe it’s me, maybe I’m the problem.”
He added: “I went to this guy, and it was what I can only describe as a Harley Street quack.
“He had a sort of attic room and he had these little jars of things and each of them would say things like ‘Apple’, ‘Dust’, ‘Cats’, ‘Cheese’.
“He went ‘I understand you’ve got allergy problems, do you know what allergies?’ I said ‘I think maybe dust’.
“When he got out his dust jar,of course, true enough, that I was the one that informed him I was allergic to dust. He went ‘Oh yeah, dust is the problem’.
“I just wish I hadn’t told him that dust was the issue, I wish I’d said ‘you tell me’.
“At one point he was doing this bullsit test on me that I knew was cap and I remember looking out of his window.
“And kind of rolling my eyes as if to say ‘If anyone’s watching I know this guy’s a lying piece of s*it and I’m not falling for it.”
He told the My Mate Bought A Toaster podcast: “It subsequently turned out it was the mattress.
“Once I finally got rid of that mattress life was never the same again.
“It was like a knock-off version of one of those Tempur-Pedics.
“I think it basically had started to disintegrate.”
READ MORE: Fears for kids’ safety after mystery 8ft deep hole found on beach used in filming of Poldark