'Jamie and Jools Oliver are delighted to announce that they are expecting their fourth child.' The baby is due in September.

Names could be interesting if it does turn out to be a boy as the couple have a fondness for ones with a floral theme.

Petal's sisters are called Poppy Honey, who is coming up to her eighth birthday, and Daisy Boo, who will be seven next month.

Mrs Oliver, 34, a model and writer, suffers from polycystic ovaries and had her first child through IVF but conceived naturally for her second and third.

Her husband, also 34, has previously said he would consider adopting a boy.

When his wife was pregnant with Petal, he said: "It would be great to have a boy, as I am in a totally oestrogen-filled house. But I really don't mind as long as it's healthy.'

He joked that he needs another man in the home as 'back-up' when he gets bossed around by the girls.

Oliver has also spoken of how motherhood was always his wife's greatest ambition.