Lena Headey says Harvey Weinstein's alleged sexual advances made her feel ''powerless''.

The 'Game Of Thrones' star has taken to Twitter to claim the producer - who has been accused of sexually assaulting a number of women in a 30 year period - made sexual advances towards her when they met for the first time at the Venice Film Festival.

She wrote: ''At one point Harvey asked me to take a walk down to the water. I walked down with him and he stopped and made some suggestive comment, a gesture. I just laughed it off. I was genuinely shocked. I remember thinking, it's got to be a joke. I said something like, 'Oh, come on, mate?!?? It'd be like kissing my dad!! ...

''I had always carried the thought that he'd never try anything with me again, not after I'd laughed and said never in a million years. I believed that he respected my boundary and maybe he wanted to talk about potential work.''

After the first ''suggestive comment'' and Lena turning down his advances, the 44-year-old actress was devastated when he allegedly tried it on again.

She added: ''We walked to the lift and the energy shifted. My whole body went into high alert. The lift was going up and I said to Harvey, 'I'm not interested in anything other than work. Please don't think I got in here with your for any other reason. Nothing is going to happen,' I said. I don't know what possessed me to speak out at that moment, only that I had such a strong sense of 'don't come near me.' ...

''He was silent after I spoke, furious. We got out of the lift and walked to his room. His hand was on my back. He was marching me forward, not a word. I felt completely powerless. He tried his key card and it didn't work, then he got really angry. He walked me back to the lift, through the hotel to the valet, by grabbing and holding tightly to the back of my arm. He paid for my car and whispered in my ear, 'Don't tell anyone about this. Not your manager, not your agent.' I got into my car and cried. (sic)''