Kate Beckinsale feared she'd had a stroke when she woke and couldn't move.
Kate Beckinsale
The 'Underworld: Blood Wars' was left terrified something bad had happened to her when she experienced an episode of sleep paralysis and had a vivid hallucination, but was reassured by a medic friend that she had nothing to worry about.
She said: "I had one crazy episode of sleep paralysis. I had actual auditory hallucination.
"I had just had lunch with David Walliams, who is a very good friend of mine, and he'd gone off and I went for a nap, because I was exhausted.
"And I heard him in my hotel room talking to someone and I thought, 'Oh no, they've come in...'
"I went to get up and I couldn't move at all. I thought, 'Oh my God, I've actually had a stroke. I've died...'
"Then I got up and he wasn't in the room so I called a doctor friend of mine - he's a neurologist - and said, 'What the f**k just happened to me?'
"He goes, 'Oh it's quite a common thing, it's what they used to think was a succubus or whatever - you can be in a very particular stage of REM sleep and your brain has woken up but your body hasn't yet. So you can't move and people will have visual or auditory hallucinations.
"I said, 'This isn't going to happen again, is it?' Luckily, it hasn't.
"But it was quite a moment, I have to tell you."
The 43-year-old actress - who has 17-year-old daughter Lilly with former partner Michael Sheen -hopes she will be a "really interesting" old lady in the years to come.
She told Total Film magazine: "What will I become? I'm hoping a really interesting old lady.
"One that has dyed hair and lots of little animals in her pockets."
Tagged in David Walliams Kate Beckinsale Michael Sheen