Jennifer Lopez (File Photo)

Jennifer Lopez has stepped up her personal security after receiving death threats.

The singer and husband Marc Anthony have requested 24-hour guards following the arrival of menacing letters, believed to have been sent by animal rights activists who oppose Lopez for wearing fur.

A source told the News of the World: "Jen is absolutely terrified. The death threats have demanded she stop wearing animal skin. The letters were sent directly to her home and she's scared for her life.

"Marc can see how upset Jen is, and wants to protect her. They've stepped up security all over their house and minders are watching her 24/7. Marc's doing all he can to make Jen feel safe."

Editor: Donald