Olivia Newton-John was sewn into her famous 'Grease' outfit.

The 70-year-old actress has revealed she had to be stitched into her tight trousers for the 1970s musical and then unstitched out of them every lunch time.

She shared: ''I limited myself to a few sips of water and no food, and joked that I was getting dehydrated and #2, might pass out ... At lunch, they actually had to unstitch me to eat and then re-stitch me after a bathroom trip.''

However, Olivia says it was ultimately ''worth it'' and she felt ''empowered''.

Writing in her memoir, 'Don't Stop Believin', she added: ''It felt empowering as pure adrenaline and the idea of claiming my own sexiness rushed through my body. All the men on the crew began to do double and triple takes as they turned around to stare at me with jaws that headed south. I think a sandwich or two hit the floor.''

Meanwhile, Olivia previously admitted it is ''a bit late now'' for a 'Grease' reunion.

She said: ''I think it's a bit late now. What would you do? Put us in a nursing home? I can't imagine that working now but you never know what someone could come up with. If there was a great idea then, of course, we would consider it, or at least I would. If John was up for it then I think I would be too but we couldn't do it without each other. Let's see what the future brings.''

And Olivia likened her time on set to being at a ''normal school''.

She added: ''In all honesty, it was like being at a normal school because I didn't go to one like that. At my school, there was a uniform, the boys and the girls we kept separate and the environment was very different. In so many ways it was an experience I'd never had before. The film's producer, Allan Carr, kind of created a party atmosphere with us all and encouraged us to hang out together. He'd come by every day and give us a pep talk and keep the energy up.''