"You've said you've never been in love," the fan said in a video posted to Twitter. "Has that changed recently?"
"Honestly, I wanna say I wanna talk to you guys about this stuff but it’s not just me in the relationship," Mendes responded. "There’s another person involved. I can’t say things that I feel... It’s not just me deciding you know?"
Meanwhile, 22-year-old Cabello recently teased new music on social media with a two-and-a-half minute video discussing what love means to her. Though she didn't name Mendes in the cryptic clip, many were quick to assume that she was referring to the "In My Blood" singer.
"What do I know about love? Nothing," Cabello began. "Where does the love go when it runs out? When does it leave? Why does it die? Do you kill it in one violent blow? Or is it a million unattended, unhealed little cuts and scratches?"
“What do I know about love? Everything," she said in a second beat. "It creeps into my chest uninvited and untamable."
"What I know for sure about love is that you never come out of it the same," Cabello continued. "I know that when you're in love, kissing is everything."
Following their time on stage, an eyewitness saw Mendes and Cabello holding hands before cuddling up next to each other as they took their seats. Mendes was even spotted with his arm around Cabello's shoulders as he played with her hair and rubbed her arm.
Watch the video below for more on the rumored couple.