Pop star Demi Lovato says she has a crush on actress Amber Heard.

Lovato is in awe of the bisexual `Rum Diary` actress, who is engaged to Johnny Depp, and thinks she is one of the most beautiful people she has ever seen, reports contactmusic.com.

Asked who her girl crush is, she said: "I love Amber Heard. She's so gorgeous, it's ridiculous."

Lovato is a vocal campaigner for gay rights and also revealed earlier this week that her late grandfather was homosexual and came out in the 1960s.