Mark Hoppus is now cancer-free, but when he first shared his diagnosis earlier this year, he didn't actually mean to.
Back in June, the Blink-182 bassist posted an Instagram story during a chemotherapy treatment, but it was only meant for his close friends.
Instead, he unintentionally shared the post with his million followers, who were immediately alarmed by the photo.
"Throughout the day as I'm getting chemotherapy and more bags of chemicals are being dripped into my body, other people are reaching out and they're like, 'Dude, what's going on?'" Mark told GQ.
While he took down the post as soon as he realized the error, he knew the secret was out and he had to make an official statement.
Looking back, the error was completely understandable, given the cocktail of chemotherapy drugs being pumped into his body.
"Chemo is like being on the worst international, overnight flight where you can't sleep or get comfortable," Mark explained.
He later added, "I felt so shitty. And the brain fog is so bad. The chemo brain is just heartbreaking to me because I can feel myself diminished mentally right now."
And while his initial post may have been chemo-induced and accidental, in a way he says he's grateful he was finally able to tell everyone.
“Maybe part of me subconsciously posted it to my main, but I definitely didn't do it on purpose. But I don't know. It kind of felt like a Band-Aid had been ripped off and I was able to be honest with people," Mark said.
