Rebel Wilson has claimed “it felt like Sacha Baron Cohen had sexually harassed me” on the set of their 2016 film Grimsby.

The Australian actress has written a memoir called Rebel Rising in which she accuses the British comedy star of incidents of inappropriate behaviour when she played his on-screen girlfriend in the Louis Leterrier-directed film.

A representative for Baron Cohen has described the claims as “demonstrably false”, in a statement given to the PA news agency.

The Pitch Perfect and Bridesmaids star said her aim was not to cancel Baron Cohen with her recollections in the memoir, released in the US on Tuesday, but to retell an experience which made her feel “completed disrespected, which led to me treating myself with even more disrespect by eating in an extremely unhealthy way”.

Wilson said she first met Baron Cohen in 2013 at a dinner party hosted by British comedian Matt Lucas, describing the Borat and Ali G actor as her “idol”. Lucas and Baron Cohen had been at school together in London.

The actress said 52-year-old Baron Cohen called her a year later to offer a role in Grimsby, which was released in North America as The Brothers Grimsby.

She played Dawn, the girlfriend of Baron Cohen’s character Nobby, a football fan who gets drawn into the world of his secret agent brother. Baron Cohen’s wife Isla Fisher also had a role, alongside Mark Strong, Penelope Cruz, Ricky Tomlinson and Johnny Vegas.

During filming in Cape Town, South Africa, Wilson claimed she felt every time she talked to Baron Cohen “he’d mention that he wanted me to go naked in a future scene”, which she claimed was in “no way essential” to the film’s plot.

She said she felt the actor would give “gross directions” in scenes which were either derogatory to women or to her size.

The 44-year-old also claimed it appeared Baron Cohen “wanted me to look and feel awful”, allegedly making her change into shorter and smaller clothes “where you could see as much cellulite as possible”.

Wilson detailed a particular incident on set where she claimed she was “lured” out of her trailer into an unfurnished concrete room with a mattress on the floor, with the only people in the room being Baron Cohen “and his mates”.

Allegedly Baron Cohen pulled down his trousers as his friends recorded on their phones, telling Wilson: “OK, now I want you to stick your finger up my ass”, for a scene that he said would be in the film.

Wilson, who said she was “scared”, claimed there was no director or film crew around during the incident, adding: “It’s my opinion that Sacha Baron Cohen gets off on making people feel uncomfortable.”

A representative for Baron Cohen told the PA news agency: “While we appreciate the importance of speaking out, these demonstrably false claims are directly contradicted by extensive detailed evidence, including contemporaneous documents, film footage, and eyewitness accounts from those present before, during and after the production of The Brothers Grimsby.”

Comedy actress Wilson refused to promote the film, adding she felt it was the “only power I had left in this situation”, but claimed she was left feeling “scared” again when an associate of Baron Cohen “threatened” to ruin her reputation with big Hollywood studios.

Wilson said she did not want to be labelled a “troublemaker” at the time, but shared a version of her claim on social media platform Twitter during the #MeToo movement in 2017 without naming Baron Cohen because she said she knew he was “litigious”.

She said she is now sharing her alleged experiences because “the more women talk about things like this, hopefully the less it happens”.

In the memoir, Wilson also describes other comedy actors such as Ben Stiller as a “total gentleman” on Night At The Museum: Secret Of The Tomb, and said Will Ferrell “could not have been lovelier” when producing Bachelorette.

She also listed “lovely” encounters with Seth Rogen, Jason Segel, Bob Saget, Robin Williams and Garry Shandling.