The 26-year-old, who gave birth to baby Harlow in January, is believed to have wanted to fall pregnant again quickly so her daughter could have a sibling of a similar age.

Nicole, who is engaged to Good Charlotte singer Joel Madden, sent the rumour mill into overdrive after she was pictured out and about in Hollywood looking less than her glamorous self.

The star, who is usually snapped looking red-carpet ready, was spotted wearing a flowing maternity-style top and comfy sheepskin boots.

An onlooker said: “She ordinarily goes for tight T-shirts and vest tops.”

The best friend of Paris Hilton became a tabloid favourite in recent years for her wild-child antics and stick-thin figure.

Yet since Nicole giving birth to daughter Harlow five months ago, Nicole has ditched her wild-child lifestyle and become a model Hollywood mum.

The loved-up mum is set to marry her 28-year-old rocker boyfriend this summer.

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