Yungblud had ringworm when he first met Billie Eilish.
The '11 Minutes' hitmaker has reflected on his friendship with the 'Bad Guy' singer, and he recalled contracting the fungal infection - which causes a rash on your skin - in a model room when he was touring in 2018.
Speaking to Spin magazine, he said: “Every artist that’s around now that’s big is there because they say something or perform like a God.
“I’ve known Billie since she was in f****** dungarees. Billie’s known me since I broke my leg and I was driving around America in a wheelchair on my first tour [in 2018] in a fucking van, staying in Motel 6's, getting ringworm.
"I got ringworm now. It comes back because of the f****** Motel 6's."
He insisted his "mission" in music is to win over his critics, and offered a word of warning to anyone doubting his "authenticity".
He added: “Don't you f****** dare question my authenticity. ‘Cause I got to fucking put cream on. You know what I mean?
"My mission is to make those people slagging me off wearing a Yungblud t-shirt next year, because it's not about telling them to f*** off. It’s about going, ‘Stop hating, get on the dance floor.’ "
Meanwhile, he pointed to the way he feels misunderstood by various scenes and fanbases, despite Sir Mick Jagger previously hailing him as proof that "there is still a bit of life in rock and roll".
Yungblud explained: "To Exploited fans, I’m a f****** poser,” he says. “To fucking Ariana Grande fans, I’m scary.
"Ask any great, true, rock and roll artist. They’ve been ridiculed. But this is real. You saw it last night [at the show].
"Everyone’s dressed like each other, but there’s a thousand cultures in a room. It’s f****** liberating.”