With her 40th birthday only 13 months away, actress Jennifer Aniston is cluckier than ever.

Having watched her former husband Brad Pitt blossom into a family man, and her friends Courteney Cox and Sheryl Crow experience motherhood, Jen is gearing up for a baby in 2008.

And as she arrived at a luxurious resort in Mexico to holiday with Courteney and her family - with a mystery man in tow - the rumours were swirling thick and fast as to whether she may already be pregnant and if her new man is the father.

'She looked quite round in the tummy,' a fellow resort guest says. 'She kept touching it and often draped a towel around her or wore a long vest, which set tongues wagging.

'We're used to seeing her flat stomach and her amazingly toned body, so to see her tummy sticking out made us think.'

A friend notes Jen was not smoking while on holiday.

'Jen's been a smoker for a long time, so to see her with no cigarettes makes me think she's pregnant,' the friend says. 'I hope she is. She deserves happiness.'

The star's been gearing up for becoming a mum for a while, telling her agent she's focusing on her personal life and that she plans to work less from now on.

She's already moved out of her Malibu beach house and into a spacious Beverly Hills mansion, complete with a big garden and a more child-friendly interior.

And there's no shortage of potential dads in Jen's life.

Her mystery man spent Christmas and New Year holidaying with Jen, Courteney, Courteney's husband David Arquette and their daughter Coco - a sign he's in it for the long haul.

Vince Vaughn, her on/off love for the past three years, is also a candidate. As are 300 star Gerard Butler and Sex and the City hunk Jason Lewis, both of whom she's been dating.

'Jen's always shrugged off talk about finding a second husband,' a pal says. 'She was heartbroken when Brad left. But she's been sounding increasingly desperate to find a man, even saying she's given up on looking for a perfect guy and is just looking for one she could be happy with.

'It's the same with babies. Jen used to joke how unprepared she was for motherhood, but since Sheryl Crow adopted baby Wyatt, that's changed. Courteney used to be the only one in the group with a baby, but now Jen's the only one without one.'
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