Ashlee Simpson-Wentz has blasted critics of her sister's weight.

The singer-and-actress hit out at people for mocking Jessica Simpson's heavier frame, insisting the voluptuous star looks "incredible".

She said: "It's disgusting that people would say those things. My sister has an incredible body. I feel sorry for anyone who would judge her, because she's one sexy lady."

The slender star - who is married to Fall Out Boy star Pete Wentz and has a son, Bronx Mowgli, who turns one later this month - is happy with her current physique but insists she won't mind if she gets heavier in the future.

She added: "There's gonna be a time when I'm way curvier, and that'll be sexy, too."

Ashlee attributes her acceptance with her shape to her husband's attitude.

She added to America's Women's Health magazine: "Pete isn't worried about stretch marks. He always makes me feel good."