However, fans can breathe a sigh of relief, for unlike Demi Moore and Natalie Portman, the perky actress has not shaved her head, but was only wearing a bald cap.
The 35-year old star plays a mother who shaves her head to support her deathly-ill daughter in the film, My Sister's Keeper, reports the New York Daily News.
Unknown actress Sofia Vassilieva plays Diaz's on-screen daughter who battles leukaemia, while Little Miss Sunshine star Abigail Breslin plays her other daughter.
The film is based on Jodi Picoult's best-selling 2004 novel of the same name.
Text: ANI | Photograph: Getty Images