Jason Biggs' wife Jenny Mollen has lost an ''inordinate amount of weight'' due to a suspected thyroid condition that made her feel like she was on ''cocaine.''

The 38-year-old actress was forced to seek medical help when a huge bulge appeared in her neck last week and she realised her ribs and hip bones were poking through her flesh - just five months after she gave birth to her second child Lazlo.

Taking to her Instagram account, she uploaded a photograph of her putruding bones and wrote: ''Not anorexia, it's a thyroid issue. I don't know what it says about me that I got this thin and didn't think there was anything wrong.

''Last Friday, I had a bulge in my neck that finally got me to the doctor. I'm STILL waiting on blood work but my doc thinks it's Graves.

''If you just had a baby and have lost an inordinate amount of weight, feel like you are on cocaine, are suddenly heat intolerant, can't stop losing hair, and think your husband is being a d**k it might just be your thyroid!! (sic)''

Graves' disease is an immune system disorder that results in the overproduction of thyroid hormones - also known as hyperthyroidism - and can cause dramatic weight loss, anxiety and irritability, heat sensitivity, a tremor and an enlarged goiter.

Jenny hasn't had the easiest of times since falling pregnant with Lazlo last year as she admitted before she had given birth to him that she was battling with depression.

The 'Crazy Stupid Love' star - who also has four-year-old son Sid with Jason - said at the time: ''One thing I really want to talk about that I feel isn't addressed enough to anybody who is pregnant right now, is that I could already be in depression. I'm sorry it's true. But I am also anticipating within the next four weeks possibly taking a major emotional dive. I think it is chemical, people don't talk about it enough.

''I guess I'm preparing myself now. I actually think I got myself sick because I got myself so stressed out about having another baby. Because having a baby is the scariest f**king thing that can physically happen to a woman.''