Stormzy has revealed technical issues during his historic Glastonbury headline set made it the "most difficult thing" he has done.
The 26-year-old, who became the first-ever UK rapper to top the Worthy Farm bill, said his in-ear monitors failed in the early part of his set.
This meant he couldn't hear himself for most of the performance.
Despite producing a thrilling and thought-provoking set, he walked off stage thinking he'd "blown it".
"The thing about Glasto, and I've not told anybody this, but I had no sound," he told Q Magazine.
"My in-ears blew after about 20 minutes, so I had no sound for the whole thing. It was the most difficult thing I've ever done.
"When I walked off stage, I thought I'd [ruined] it. I thought it was the worst thing I'd ever done."
He added: "I came off stage and thought I'd totally, absolutely, blown it. I was crying for, like, an hour. I was in hysterics.
"I thought I'd [messed] it up. Heartbroken, man. Heartbroken."
All right on the night
The performance tackled institutional and historic racism in the criminal justice system and in the arts.
Wearing a Banksy-designed Union Jack stab-proof vest, he ripped through tracks from his number one debut album, Gang Signs & Prayer, and a cover of the UK garage classic, Sweet Like Chocolate.
As well as bringing out Coldplay's Chris Martin, and fellow London rap stars Dave and Fredo to perform their number one single, Funky Friday.
However, it wasn't until he spoke to festival organiser Emily Eavis afterwards that the artist - whose real name is Michael Omari - realised his big night had in fact gone "all right", he explained modestly.
"Then after calming down for an hour," he went on, "Some of the people at the festival, Emily Eavis and that, gave us a memory stick to watch it back.
"And I got about halfway through and I was, like, '[Oh], I think it all went all right'."
On Tuesday, Stormzy, announced his second album, Heavy Is The Head, will be released on 13 December.
The album's cover image, posted to his 2.6 million Instagram followers, sees the bare-chested star wearing a crown and looking down at the aforementioned Banksy-designed stab vest from his June show.
The record, which features the likes of Ed Sheeran, Burna Boy, Yebba, H.E.R. and Aitch, closes with his one of his latest number one singles, Vossi Bop.