George Clooney's wife Amal watches old episodes of her husband in 'ER'.

The 56-year-old actor portrayed Doctor Doug Ross in the popular TV drama for five years before he quit the programme in 1999, and the hunk has revealed ''every once in a while'' when the couple are travelling across the globe his 39-year-old spouse will catch up on the show.

Speaking to Vanity Fair magazine about Amal's obsession with the programme, he said: ''Every once in a while, Amal - because she didn't really watch television during that period of time - will see it on TV, usually in Europe.''

But the couple - who have three-month-old twins Alexander and Ella together - both ''laugh'' when they watch the reruns of the show because they compare how the 'Ocean's Eleven' heartthrob has ''aged a lot''.

George added: ''And she'll see it and it just makes us both laugh, because I've aged a lot in [the years since]. Yeah, she got me 10 years after that guy, thank God.''

And the 'Suburbicon' director has revealed he has noticed the signs of ageing have started to show themselves on his face, as he has realised his hair colour has changed to being completely white, whilst his eyebrows are starting to change shape as he matures.

Speaking about his appearance, he said: ''I do have [hair], but it's white and my eyebrows are changing shape.''

But the star never thought he would be a father and married at his age.

Speaking previously about how his life has mapped out, he said: ''Suddenly, you're responsible for other people, which is terrifying. Amal's like an Olympic athlete. She's doing so beautifully.

''Right now my job is changing diapers and walking them around a little bit. I really didn't think at 56 that I would be the parent of twins. Don't make plans. You always have to just enjoy the ride.''