The pop-punk musician, known for songs including Cotton Candy and Fleabag, has had two number one albums in the UK chart with Weird! in 2020 and his self-titled album in 2022.
But in the interview, he reflected on how difficult it was to be a young person today with "so much anger" and hate in the comments of social media videos.
Asked what his hardest moment had been, he said: "I'll never forget, someone came to me in a pub in east London and just was like, 'your music is terrible and I don't believe you and I hate it'."
He said he was left feeling "like a wounded animal" where you "try and lick yourself and bring yourself back to it".
Whereas back then, aged 22, he responded with a tentative "oh, yeah, cool like", now he feels confident not to "give them the power of a reaction".
Ahead of the release next month of his new album, Idols, he said one of the themes behind it was to "embrace my masculinity, which is a crazy thing to say in 2025".
"Honestly I am so proud of what we've created," he said of his young fanbase.
