The Mission: Impossible 2 star played the comedian's love interest in the film, but there was no love lost behind the scenes as she tested his good nature at all times.
She says, "He was the most frustrating victim of my pranks... I had a lot of time to wait, unfortunately, in the trailer, so while Simon was on set I'd be in the trailer sort of inventing the next prank. I did everything.
"I created a human stool out of a king-size Mars bar and placed that in his toilet bowl with a little apple juice around the edge for authenticity... It was a prank and a snack all in one.
"I would look through my curtains in my trailer and wait for Simon to get off the set, come to his trailer, knowing that he's gonna walk into his trailer, look into the bathroom and be appalled... He'd always come out as if nothing had happened... He'd never give me the satisfaction."
But Newton's pranks didn't end when the movie wrapped - she carried them on when she and Pegg were promoting the film six months later.
She explains, "We were doing the press for the film and on a press junket the actor sits in a hotel room and then the different journalists come in with you, so you're there all day with the same crew. You've got your little seat and your water. So the night before I went to a supermarket and brought some really cheap brand vodka... I got there (to the junket) early, went into Simon's hotel room where he was going to be doing his press junket and replaced all the mineral water bottles with vodka.
"It's actually on film; they put in on the Dvd as added extras... He comes into the room, sits down... and you get your bottle of mineral water, straight away, and you fill up your glass for the day. So he filled up his glass, took a huge gulp, at 8.30 in the morning, and immediately, he hadn't seen me for six months, the first thing out of his mouth was, 'Newton'."