Shawn Mendes has reiterated that he is not gay and has admitted that he finds ongoing speculation about his sexuality "so, so frustrating".

The 22-year-old singer has been in a relationship with Camila Cabello for more than a year but has been dogged by accusations that their romance is a PR stunt, possibly designed to hide his sexuality.

Talking to Dax Shepard on his Armchair Expert podcast, Mendes said that the rumours make him angry on behalf of gay people who are genuinely still in the closet.

"It was so, so frustrating for me because there were some people in my life that I was very, very close to... who were gay and in the closet," he said. "And I felt this real anger for those people.

"You want to say, 'I'm not gay but it'd be fine if I was gay. But also, there's nothing wrong with being gay but I'm not.' You don't really know how to respond to the situation."

He continued: "Everyone's been calling me gay since I was 15 years old. I'm not gay and I'm like, 'What does that mean?' I had these problems with the way my voice sounded.

"I'm like, 'How do I sit?' I'm always first to cross my legs and sit with a position of this feminine style and I really suffered with that shit.

"I think a lot of guys go through that and, even worse than that, there are so many guys who are gay and in the closet and must be hearing shit like that and being like, 'I'm terrified to come out.'"

Earlier this month Mendes and his girlfriend released their latest duet, a cover of 'The Christmas Song'.