Hailee Steinfeld may be a pro at navigating the acting scene, but when it comes to music, she's a newcomer -- so it's totally understandable that she still gets pre-performance nerves.

Hailee took the stage last month at iHeart Radio Music Festival to perform "Stitches" alongside her friend Shawn Mendes. The two teamed up to perform an acoustic version of the tune a few months back, which was basically pop perfection and completely comfortable for Hailee. But taking their duet to a big stage, in front of thousands of fans, was a bit different for the "Love Myself" singer.

Hailee recently admitted to us that she was super nervous to hit the stage -- not just because it was only her second time performing in front of a live crowd, but because she's a huge fan of the Canadian singer and his hit song.

"He's one of my favorite artists and that's one of my favorite songs," Hailee admitted. "It's hard when you admire something and someone. You want to do it justice."

Luckily, Shawn was "so genuine and supportive" of Hailee, who's working on her upcoming debut EP, and he instantly helped put her mind at ease.

"He's like, 'Are you nervous?' and I'm like, 'I don't know if I should say 'yes' because I'm about to go on and do this with you, but I'm completely terrified," she said. "He's so awesome, that was really such a blast."