Handed fame and fortune at such a young age, your average starlet has two options: a) make the most of it while it lasts, date everyone in sight and hit every nightclub in town, or b) pick a good man, bolt the doors and hide.

Having dated Brian Austin Green, 35, a fellow actor, since 2004, Fox clearly chose the latter, more sensible, option, but she makes it sound incredibly hard. “I have no friends and I never leave my house,” she confesses. “You just have to make a choice to just refuse to be involved with things that could get you in trouble. It’s easy when you feel upset or depressed about something to want to go to a club and want to drink and want to build a disconnect that way. But instead I just force myself to sit and feel it and deal with it, and try and grow from it, because I don’t want to go down that path.

“And, yeah, it’s difficult. I’m one of the most isolated people in existence right now. But it’s worth it. Because if I wasn’t making that decision I would be throwing away my career.”

Fox could already be tiring of the restrictions, however. She recently broke off her engagement to Green and although they are now back together, she claimed: “I’m just not the marrying type.” Earlier this month, in yet another Jolie parallel, she said she was bisexual.

Her looks may have taken her a long way, but Fox says she won’t be selling her diet and beauty secrets to any glossy magazines. “I didn’t even train for this role,” she laughs. “Just quit smoking — that’s all I did. My weight fluctuates constantly. I don’t really take good care of myself. I’m not that type of girl, I don’t pamper myself, I don’t have a special diet, I just sort of exist and survive. Whatever happens, happens.”

My stuff

On my MP3 player

Nirvana. I’m a diehard rock fan

On my DVD player

Terminator: The Sarah Connor Chronicles (the American TV series that starred Brian Austin Green, Fox’s boyfriend since 2004)

I will never throw away

I’m not a sentimental girl

My life in cars

Chevrolet Camaro

Fox drove this 1976 car in the first Transformers film

Mercedes G-Wagen

She owns one of these rugged off-roaders, originally designed as a military vehicle in the 1970s

Ducati Monster 696

Fox’s latest purchase is this 695cc, 120mph Italian motorbike