In a new Rolling Stone cover story, the 20 year-old heartthrob singer talked about the constant speculation he is closeted."In the back of my heart, I feel like I need to go be seen with someone — like a girl — in public, to prove to people that I'm not gay," he said. "Even though in my heart I know that it's not a bad thing. There's still a piece of me that thinks that. And I hate that side of me."To be fair, Mendes isn't very comfortable with any attention on his personal life, including his short-lived relationship with model Hailey Baldwin.A month after the pair attended the Met Ball together, Baldwin was engaged to fellow singer (and her former boyfriend) Justin Bieber.The pair have since married and Mendes said he bears no ill will.Justin Bieber confirms he is a 'married man'"I texted Hailey, 'Congratulations,' and I really am happy for them," he said. "She's still one of the f***ing coolest people ever — she's not just a beautiful person visually, but she's one of the most beautiful hearts I've ever met." It's not the first time the "Treat You Better" singer has addressed rumors about his sexual orientation.As the Rolling Stone story noted, last Christmas Mendes felt compelled to record a Snapchat story in response to YouTube commenters. "First of all, I'm not gay," he said in the social media posting. "Second of all, it shouldn't make a difference if I was or wasn't."But far from shutting down the chatter, it just amplified it. Mendes said he now finds himself trying to avoid feeding into the talk.He also agonized after he gave former tour mate Taylor Swift permission to post a video of Swift putting glittery eye makeup on his face backstage during her recent "Reputation" tour. "I felt sick," he said. "I was like, 'F**k, why did I let her post that?' I just fed the fire that I'm terrified of."Mendes said he was ultimately fine with it and revealed that he grew up with 15 female cousins, "braiding hair and painting nails.""Maybe I am a little more feminine — but that's the way it is," he said. "That's why I am me."