Mark Hoppus Reveals His Cancer Announcement Was Actually an Accident: 'The Brain Fog Is So Bad'

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When Mark Hoppus told the world he'd been diagnosed with cancer, he meant to share the news with a close circle of friends — not his 1.2 million Instagram followers.

But that's exactly how fans learned of the Blink-182 rocker's illness, as he accidentally posted a photo of himself strapped into a chemotherapy chair to his Instagram Story in late June.

"Throughout the day as I'm getting chemotherapy and more bags of chemicals are being dropped into my body, other people are reaching out and they're like, 'Dude, what's going on?'" he recalled in an interview with GQ.

Hoppus, 49, has since announced that he is cancer-free following months of treatment for stage 4 diffuse large B-cell lymphoma, the diagnosis for which he received in April.

But when he accidentally posted, Hoppus, 49, was still not totally aware of everything he was doing, as Benadryl and chemotherapy had made him forgetful.

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"Chemo is like being on the worst international, overnight flight where you can't sleep or get comfortable," he told the magazine. "I felt so s—y. And the brain fog is so bad. The chemo brain is just heartbreaking to me because I can feel myself diminished mentally right now."

Still, he told GQ that getting everything out in the open was a relief of sorts.

"Maybe part of me subconsciously posted it to my main, but I definitely didn't do it on purpose," he said. "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."

At the time, Hoppus shared a statement to social media, writing, "For the past three months I've been undergoing chemotherapy for cancer. I have cancer. It sucks and I'm scared, and at the same time I'm blessed with incredible doctors and family and friends to get me through this."

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In the months since, Hoppus has said that he and former Blink-182 bandmate Tom DeLonge have repaired their friendship, with the musicians telling GQ that they enjoyed a sit-down in Hoppus' backyard with drummer Travis Barker.

"I was like, 'Oh s—, band meeting!" DeLonge said. "We got into more life stuff. What we've learned over the years about ourselves. How we've grown, how nothing really matters when it boils down to what we were dealing with in that moment. And so, it wasn't some big meeting about Blink-182, it was more about brothers meeting and saying, 'How do we support Mark?'"

Hoppus has slowly but surely begun his return to the stage, and in October, donned a Batman suit to sing Blink hits with Barker and Kevin "Thrasher" Gruft in what was his first performance since he announced he was cancer-free.