Skinny Nic Calls In Docs

Nicole RichieNicole Richie is fed up of people saying she's skinny.

But now she's doing something about it.

The waif-like star has decided to undergo "diagnostic treatment" to find out why she's not putting on weight, her spokesperson said.

"She is working with a team of doctors and specialists whose focus is nutrition... this is not a treatment for an eating disorder," her rep told People magazine in the US.

But Nicole is keen to point out that this does not mean she's gone into rehab: "Contrary to CNN's false accusations, I did not check myself into an eating disorder rehab," she said on her My Space blog.

A friend of Nic's told People mag: "She's tired of everyone saying you don't eat, because she does. She wants to gain weight.

"It wasn't about anyone saying you have to do this - it wasn't an intervention.

"It was her saying 'I'm tired of people saying this about me, I'm going to get some tests.'"

In May, Nicole, 25, admitted to Vanity Fair that she was "too thin" and wasn't happy with the way she looked.