Smash hit

Was that bravery or merely a resigned acceptance that as a celebrity, nothing is private? She shrugs. "You either face it head on or you hide until someone catches you." Or to put it into the language of someone who loves to shop, she adds: "You can cry or think, 'Can I accessorise?' I have earrings, headscarves and make up."

She has also taken the opportunity to offer support to other women suffering from alopecia in the way she knows best. Among her future projects is a documentary for Channel 4 in which she will be followed around for six months by a camera crew, recording how she deals with her condition.

Thinning hair is, as she points out, a common problem. Often caused by stress, it affects one in four women in the UK and is usually spotted between the ages of 15 and 35.

"I think it's not easy for everyone. When you first come out with no hair, you get shell-shock with everyone staring. But I have a good bunch of friends around me.

I have lost my hair, but I am still the same person," she says.

Just before heading off to America for work, Porter's mother, Sandra, came down to London to collect Honey and take her to Edinburgh. It was the first time she had seen her daughter up close with no hair.

"She saw me for the first time face to face when she came down on Friday to take Honey up to Scotland. I went to her, 'Are you okay with my hair?' She said, 'Yes, you are still you'. And then she said, 'It's a mix between chemotherapy and Matt Lucas'. I replied, 'So not Natalie Portman and Sinead O'Connor?' If you can deal with that, you can deal with anything."

There is also the distraction of work. Porter says she is happiest when she's at work. "I think so. I do like work. Now I have got Honey so it is always a work day.

"She comes to the US, she has been out 20 times and she's only three. She loves it. But when she doesn't come I miss her. She is at that age where she prefers going to grandma. I say, 'I am going to the US', and she says, 'Yay, I'm going to see grandma. Bring me toys from America'."

Honey has also been a source of strength for the recovering Porter. She was worried how her daughter would react to her bald mother, but she took it in her stride.

"My daughter says, 'You're bald', and I say, 'Well you've got a snotty nose'. She thinks that's funny."

Porter's latest television venture has the editorial thrust of a special feature in The National Enquirer. It centres on the notion of tracking down the spirits of dead celebrities. Previous targets have been predictable enough, including Al Capone, Marilyn Monroe, John Lennon and Elvis, while this series will pursue the troubled spirits of James Dean, Clark Gable and Judy Garland.