Williams, 30, was recently booted off the UK dancing show and lost a considerable amount of weight due to the gruelling training that she had to do for the show.
Asked if she lost weight on the show, she said: 'Yeah, a bit. I was hoping not to. I've toned up, though. Now there's no more weight on me that I could lose!'
She said to UK's Heat magazine: 'I'm 120 pounds [8st 8lb], but yes, I'm too skinny. I've always been like that. Growing up, I was so skinny - I was always skinny, skinny, skinny.
'I've always wanted to be a little bigger, so now I'm eating lots of pasta and rice. I want to gain weight.'