Jason Isaacs accidentally fell asleep mid-scene while shooting 'Red Dog: True Blue'.

The 53-year-old actor is a ''terrible insomniac'' who finds it impossible to nap, but was hit hard by jet lag when he flew to Australia to shoot the family comedy.

He said: ''I never go for a nap. I wish I could. I'm a terrible insomniac.

''But I have fallen asleep in a scene.

''In fact, on 'Red Dog', I had just got to Australia from England, and we had a scene in which I'm watching the original 'Red Dog' with the kids.

''There was a long tracking shot, and when they got to the end they thought I was taking a very long, dramatic, pause. And then they all realised I was fast asleep.''

Jason - who has daughters Lilly and Ruby with partner Emma Hewitt - also tries to get mobile phone use incorporated into his scenes because he hates being parted with his device for any length of time.

He said: ''I try to make sure my character uses my phone.

''I'm always going, 'Well, maybe he'd use this phone' so I can have it there.

''I'm a 'Words With Friends' addict and I FaceTime my kids.

''I'm mostly way, so I want to be available whenever they can deign to spare me eight seconds to ask me where something is in the house.''

And the 'Harry Potter' star admits he hates shopping for clothes so much, his wardrobe mainly consists of his old costumes.

He told Total Film magazine: ''I don't like to shop for clothes. I only wear things characters have worn before, that they tell me I can take home at the end of a shoot.

''It's just because I don't like to shop for clothes. At the end, I go, 'Can I have those jeans? Because they fit me.' ''