Miley Cyrus is said to be worried about the other woman in her boyfriend's life.

The singer's beau Liam Hemsworth is devoted to her, but has to spend a lot of time with his The Hunger Games co-star Jennifer Lawrence.

The upcoming action thriller is set to be a global hit, and the cast have been spending a lot of time promoting it of late.

According to In Touch magazine, it's not just on a romance level that Miley is concerned about Jennifer.

She is also mindful about the success the young actress is garnering.

"Miley is threatened by Jennifer's career and confidence," a source told the US publication.

While Miley's last move The Last Song was not a box office standout, Jennifer's role in the 2010 drama Winter's Bone earned her an Oscar nomination.

"Jennifer has replaced her as Hollywood's It Girl," the friend added.

"And now Miley is terrified that she'll replace her as Liam's girlfriend too."

Liam has previously called Jennifer "an incredible person and ridiculously talented."