The singer-songwriter, 27, was on the show to talk about his album Seventeen Going Under.
But he confessed he was a little the worse for wear because he’d been out celebrating the fact that Newcastle United had been taken over by new owners.
“We did Jools Holland and then went straight up to St James's. I got on the statue and started playing Local Hero and 5,000 Geordies just started singing along… because (Mike) Ashley's out," he said.
Newcastle fan Sam Fender took part in the celebrations following news of the club takeover yesterday.
He told #BBCBreakfast he’s a little worse for wear this morning. 🥴https://t.co/7yB6RJhdnB pic.twitter.com/xhiMqFlX8N
— BBC Breakfast (@BBCBreakfast) October 8, 2021
"I did about a thousand selfies, got proper mobbed, but everyone was absolutely class and they gave us a lot of cans and I'm really hungover, I’m really really hungover."
"These things happen don't they," he added.
Fender also had a bit of a warning from Charlie Stayt at one point in the interview, when he used the word “cr******”.
“Mind the language is all I'll say in the most friendly way possible,” the presenter said.
Viewers were thoroughly amused by the star’s behaviour.
“Absolutely crying and loving the Sam Fender interview on BBC Breakfast,” one person tweeted, while another fan said they were “proper chuckling” and that it had made their day.
”Legend turning up to BBC Breakfast hungover!” said another, adding: “Well done for getting through that!”
"Love @samfendermusic even more after appearing on the couch on @BBCBreakfast with a stinking hangover from celebrating with NUFC fans at St James Park the night before,” said another.
“What a legend.”
Watch: Newcastle fans celebrate club's Saudi takeover