Nicole Richie has checked into a treatment facility to address her nutrition problems.

The reality TV star has denied claims that she is suffering from an eating disorder but wants doctors to help her to find out why she can't put on weight.

"It is important to Nicole that she achieves this goal in a healthy way as this is not a treatment for an eating disorder," her publicist explained in a statement. "She is working with a team of doctors and specialists."

Filming for the fifth series of The Simple Life has been postponed while Nicole undergoes treatment.

A 20th Century Fox spokesman said: "We wish her a speedy recovery and expect production to resume soon."