Geraldine James photo

Actress Geraldine James, 64, lives in London with her husband, the director Joseph Blatchley. They have a grown-up daughter, Ellie. Geraldine James stars alongside Sheridan Smith in Black Work - a new ITV drama about undercover policing which starts tonight at 9pm.

Here are five things you didn't know about Geraldine James...

Geraldine feels much fitter at 64

'I've just taken up running - and absolutely love it. In my new TV series, Black Work, there's a scene where my character goes for a run. I thought, ‘Oh, blimey! I'm going to get a sprained ankle.' So I spent a morning running and loved it. It makes me feel so much better and in tune with my body. I love walking, too, and pilates, which I've been doing for two years now with my daughter. It puts you back in touch with yourself. I've become much fitter as I've got older, funnily enough.

At the beginning of last year, I got bored with myself and wanted to do something different. So I went vegan for three months and gave up alcohol, caffeine, dairy, wheat and meat. It was fantastic; I loved it. Then my doctor said, ‘You need to eat meat, actually.' When you're in your sixties, you need more protein. I've also bought myself a Nutribullet and make my own smoothies. I made one the other day with kale and it was disgusting. Coconut water with some carrot and ginger is wonderful but keep the kale for supper.'

Geraldine isn't a great sleeper

'I have an overactive brain that keeps me up at night so I've been doing mindfulness. I have an app - Headspace - that I spend 10 minutes a day doing. I've got my husband on to it, too, and ask him, ‘Have you done your Headspace?' And he says, ‘No, I haven't got time.' But that's the point - everyone has 10 minutes a day to be quiet somewhere.'

Geraldine stars alongside Sheridan Smith in police drama, Black Work

Geraldine has found the secret to a happy marriage

'The secret to a happy marriage is friendship and laughter. There's no alternative. I've been with my husband, Joe, for 39 years. It's wonderful to be with someone who I love and all the rest of it, but who is also hilariously funny and my best mate. He was in the third year at Drama Centre and I was in the first, and I thought he was a bit arrogant. Then a few years later we met up again and that was that.'

Geraldine is stepping out of her comfort zone for Black Work

'I've never played a police person before Black Work, and certainly had never worn a uniform. ‘Black work' is how they describe the undercover work done by the police, and I play the chief constable. Wearing a uniform was challenging and interesting. You have to embody a uniform and make sense of it.'

Geraldine can't resist an online bargain

'My favourite indulgence is internet shopping -I'm trying to wean myself off it! The good thing about buying things online is that you can send them back. They're sick of the sight of me in my local post office!'

Geraldine James stars in Black Work tonight at 9pm on ITV