Mark Davis / 1 / 5
Mark Davis / 1 / 5

It's official: Chris Martin and his band, Coldplay, have a new big fan and her name is Jennifer Lawrence.

The "Hunger Games" star was in Las Vegas on Friday with the Coldplay frontman, checking out his performance at the iHeartRadio music festival at MGM Grand. Earlier in the week, Jennifer saw the band play a sponsored show in Los Angeles, as well. While they've maintained a low profile, the couple has been seen out since news of their relationship became public.

RELATED: Lawrence and Martin take their romance to Coldplay concerts

"She watched the show from the side of the stage," a source said, "and she watched the closed rehearsals, too. She's a big fan of the band. She knows all the lyrics."

Wearing a black crop top and dark denim jeans, Jennifer hung out in Chris's dressing room before Coldplay's early set and hung out afterward, too.

RELATED: Lawrence and Martin go public with new romance

"They made sure they weren't seen together," the source said. "She wasn't with him when he walked out of his dressing room to go to the stage. She walked out about two minutes after him. She was a few minutes behind him when he got done, too, but she was definitely with him when they knew they didn't have prying eyes."