Shawn Mendes was left lost and angry when trolls online determined he was gay and he should come out of the closet.

The In My Blood singer is not gay but couldn't find the right words to express his feelings without hurting his gay and bisexual friends.

"It was 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," Shawn told Dax Shepard on the latest episode of his Armchair Expert podcast.

"I felt like this real anger for those people," he explained, reflecting: "It's such a tricky thing. 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."

Sharing: "Everyone's been calling me gay since I was 15 years old. I'm not gay and I'm like, 'What does that mean?'" Shawn said the experience has caused him to self scrutinise.

"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 s**t," he revealed.

"I think a lot of guys go through that and even worse than that there are just so many guys who are gay and in the closet and must be hearing s**t like that and just being like, 'I'm terrified to come out'," he mused.