Where has all Zoe Saldana’s muscle gone?

The actress got into serious kick-ass shape for her starring role in last year’s action movie Colombiana but now she looks like she is wasting away, and her dramatic weight loss could be affecting her health, RadarOnline.com can exclusively reveal.

“She looks thin and weak, and incredibly depleted,” nutritionist Majid Ali, who has not treated the star, told RadarOnline.com in an exclusive interview.

Avatar hottie Zoe Saldana is about to kick some butt!

The sexy 33-year-old who stars in Colombiana, which hits the bigscreen on Friday, recently transformed her lean, mean bod into a killing machine for her big, action role – and Shape Magazine has all the details on how she did it straight from her trainer Steve Moyer.

Moyer, who has worked with the star since 2009, hit the gym with Zoe with three to four days a week to prep her for the physically intensive role, but insists that he didn’t have to work with her on her diet at all.