Cameron Diaz will be celebrating her 40^th birthday this August 30, and sources say she’s growing concerned about being replaced by young actresses. “She’s worried because years ago roles for older women were slim pickings for those in their 50s and 60s, but now it’s hard for actresses in their 40s to get a starting part in a film,” a source tells BettyConfidential.

The source adds that Diaz is so troubled by the lack of roles out there that she tweaked her face a bit. “You can tell there is something different about her face,” adds our source. “She’s had her nose fixed because it’s been broken several times and she’s modified her features. She’s got fierce competition and needs to stay hot.”

Read Cameron Diaz Gets Benched

 Although nips and tucks are the norm in Hollywood our source claims, “Cameron won’t admit to the surgery. Especially since she said she would never do it. But, she’s developed a lot of wrinkles and wanted to smooth those out.”

If Cameron isn’t careful she may start to look a bit plastic. “She looked natural at one time, but not anymore,” adds our source. “She thinks you have to stay young and look young to stay on top in Hollywood. She’s beautiful, but she has to look her best at all times. She’s got the perky personality that makes her come across as youthful, but the lines in her face told a different story.”

Our source adds, “Cameron told a friend, ‘I fear that I’ll only be able to voice roles like I did in Shrek.’”

While we hope Cameron allows herself to age gracefully so that she can start playing mom to Kristen Stewart, let’s take a look at some of her sexiest roles before she transitions to the big 40.