Nick Vallelonga says he is ‘incredibly sorry’ after discovery of a 2015 tweet in which he backed a false claim by Donald Trump about 9/11

Nick Vallelonga, the Green Book writer and producer whose late father Tony is a central character in the film, has apologised for a 2015 social media post that triggered accusations of Islamophobia.

Vallelonga has come under fire after the discovery of a tweet in which he backed Donald Trump’s false claim during the election campaign that in New Jersey “thousands of people were cheering” the destruction of the World Trade Center. In a widely circulated screenshot, Vallelonga wrote in reply to Trump: “100% correct. Muslims in Jersey City cheering when towers went down. I saw it, as you did, possibly on local CBS news.”

Vallelonga received widespread condemnation, particularly as one of the film’s stars, Mahershala Ali, is Muslim. One of the film’s main financial backers, Participant Media, released a statement saying: “We find Mr Vallelonga’s Twitter post offensive, dangerous, and antithetical to Participant Media’s values. We reject it in no uncertain terms.”

Facebook Twitter Pinterest Mahershala Ali, left, and Viggo Mortensen in Green Book. Photograph: Allstar/DREAMWORKS

Having deleted his Twitter account, Vallelonga issued a statement, saying: “I want to apologize. I spent my life trying to bring this story of overcoming differences and finding common ground to the screen, and I am incredibly sorry to everyone associated with Green Book. I especially deeply apologize to the brilliant and kind Mahershala Ali, and all members of the Muslim faith, for the hurt I have caused. I am also sorry to my late father who changed so much from Dr Shirley’s friendship and I promise this lesson is not lost on me. Green Book is a story about love, acceptance and overcoming barriers, and I will do better.”

Green Book – named after the celebrated guide book that enabled black motorists to avoid racial discrimination as they travelled across the US – is about an Italian-American driver/bodyguard played by Viggo Mortensen, based on Vallelonga’s father Tony, who accompanies African-American pianist Don Shirley on a concert tour in the Jim Crow-era deep south. The film won three Golden Globes: for best film (musical or comedy), best supporting actor for Ali, and best screenplay, for which Vallelonga is credited, along with director Peter Farrelly and writer Brian Hayes Currie.

Vallelonga’s apology follows one by Farrelly after a number of articles were unearthed in which Farrelly laughed off serial sexual misconduct, including repeatedly showing his penis in meetings. Farrelly said: “I thought I was being funny and the truth is I’m embarrassed and it makes me cringe now. I’m deeply sorry.”

Despite its liberal credentials, Green Book has found itself under an increasing tide of criticism, with the film’s portrayal of a close friendship between Vallelonga and Shirley being flatly denied by Shirley’s family in an interview with Shadow & Act. In the same article, Ali was reported to have apologised for any offence caused by his portrayal of Shirley (who died in 2013), and was quoted as saying: “I did the best I could with the material I had.”