Shawn Mendes and Camila Cabello revealed a bit more about their relationship during the iHeartRadio Music Festival on Sept. 19, including Mendes' jealousy of pop star Austin Mahone. The two looked more like a couple than ever before.

According to E! Online, a source has confirmed that, although Mendes and Cabello have been friends for quite some time, they are, in fact, now dating.

During a joint interview with E!, the Fifth Harmony singer fueled the relationship rumors even more when she revealed that Mendes was jealous of her relationship with Mahone.

"While we were on tour, Austin and I were dating, and Shawn was just kind of being a loaner!" she said. "Yeah, he was so jealous, and he couldn't come out on stage because he was just seething rage and crying blood."

Mendes laughed at Cabello's comment, and the stars both quickly made jokes when the interviewer told them they would make a good couple.

"We can't do that! I mean Spanish and Canadian don't really mix," Mendes joked, before Cabello added, "We actually hate each other in real life. We can't stand each other."

Interviews weren't the only interaction that the two stars shared during the iHeartRadio Music Festival. On the red carpet, Mendes took the opportunity to play a prank on the Fifth Harmony member by surprising her, Just Jared Jr reports.

Though scared, Cabello ended up laughing and proceeded to pose for pictures with Mendes soon after. The 18-year-old later retweeted a video of the prank, and before that, shared a tweet about how happy she is, leading many to believe she may have been talking about Mendes.

The Cuban-American singer also shared a photo of her and the "Stitches" singer on Instagram, in which she poses rather close with her head resting on his shoulder, as they pretend to be sleepy and in need of coffee.

Watch the moment Mendes scared Cabello as she posed for pictures below.