Image copyright Universal Pictures

Filmmaker Judd Apatow has never been afraid to poke fun at serious subjects.

In Knocked-Up he found the humour in an unwanted pregnancy from a one-night stand. In This is 40 he made us laugh about a couple going through a midlife crisis. And in 40-year-old Virgin he addressed... well, you know.

For his latest project, The King of Staten Island, the director has joined forces with US comedy star Pete Davidson to tell the tale of the effects of the latter's own personal 9/11 tragedy.

Aged seven, Davidson lost his father Scott, who died while working as a fire fighter helping to deal with the aftermath of the plane attacks on New York City in 2001. His dad was one of 2,977 people to lose their lives.

"I always think that there's comedy in the most difficult situations," says Apatow, across a three-way virtual film junket.

"That's why we like Dr Strangelove [Stanley Kubrik and Peter Sellers' dark comedy about nuclear war]. You can't have a more difficult situation than that. So that's the lens that I've always seen everything through.

"I think as a kid, I felt a lot of hostility, I didn't feel like the world was fair. But I loved comedy films and comedians and I loved that they mocked how the world worked, and they helped me try to figure it out.

"So I don't think anything is off limits, if your heart is in the right place you really can explore anything."

In the film, Davidson plays a "75% true" version of himself - a directionless grief-stricken 20-something stoner named Scott, who has behavioural issues, and lives with his mum and sister in the least fashionable of the five boroughs.

He agrees it's all a rich vein of material.

"I had similar experiences growing up as Judd, where I didn't think the world was fair and I had people like Adam Sandler and Jim Carey and Eddie Murphy and Bill Burr to point those things out to me and make it humorous," he says.

Burr, as it happens, was able to help out Davidson directly, by playing the new love interest for Scott's widowed mother Margie; played by Marisa Tomei. As if having a new man in the house isn't problematic enough, Burr's character Ray just happens to be another fireman, and of course, comedy ensues.

What initially began as "90 pages of toilet humour," written by Davidson and his writing buddy Dave Cyrus, was, with Apatow's help, turned into a "beautiful script", full of "emotion and range".

'Put that part of my life behind me'

As well as being a "love letter" to his mum, Davidson, who also has an executive producer credit, hopes the feature will allow him to draw a line under many of the mental health issues that have plagued him, very publicly, for years.

In December 2018, the police checked in on the at-times controversial SNL breakout stand-up star after he alarmed fans by posting on social media that he didn't "want to be on this earth anymore", not long after his high-profile breakup from ex-fiance Ariana Grande.

"I had a lot of prior issues and a lot of stuff that I was dealing with personally that I wanted to bring to the forefront so that I could not only make a movie but also just grow as a person," says Davidson, who has borderline personality disorder, as well as Crohn's Disease.

"What I wanted to do was maybe after we did this I could put that part of my life behind me and, not forget it, but move forward and have a new outlook on life."

Apatow believes the lead character, who daydreams about one day running a tattoo restaurant, is a fair reflection of what Pete's life might be like now if he hadn't found his comedy calling.

The pair first worked together on another Apatow film - 2015's Trainwreck, and he describes Davidson as "a funny, great, fascinating person".

That particular film gave another comic actor and writer, Amy Schumer, her big movie break, and other stars including Steve Carell, Seth Rogen, Jonah Hill and Kristen Wiig have all benefitted similarly from his direction early on.

'Something positive'

Now, with no cinematic release, due to the Covid-19 virus shutting theatres, and against the backdrop of mass Black Lives Matter protests, following the death of George Floyd, Davidson admits it's "an odd time to put something out".

"It's nice to put something positive into the world, so I hope people enjoy it," he says.

Making movies, Apatow stresses, is "one of the hardest professions to make safe", as they are "all about being close to each other, touching each other, and being in very small spaces".

The director also hopes the protests, for people who "were ignored for a very long time" ultimately "lead to meaningful change," and he urges people to vote for it in the US elections in November.

"I just hope that people are kinder to each other in the future," adds Davidson.

The thing they both miss most about the old pre-coronavirus world is the ability to simply hang out with friends at comedy clubs, where Apatow also began his career, as a stand-up. The 52-year-old jokes they'll both mark their film's online release by simultaneously pressing play on iPads from their own respective beds!

The King of Staten Island is a film about trauma, loss, and the healing qualities of opening your heart again to love and laughter.

What might Davidson's dad have made of it?

"I think if my dad was around he would get a kick out of it," says the leading man. "He would be like, 'holy crap, dude, that's crazy!'

"My dad was a huge comedy fan, so I think he would just be thrilled".

As well as being there in spirit, the real Scott is made flesh on-screen not only by his son, but also by his own father Stephen, who makes a scene-stealing cameo as Grandpa.

Apatow says: "The truth is Pete, we never talked about it... your grandfather actually would get called, you can see him as a regular on Seinfeld. He actually could have been that guy".

"Oh yeah, he'll get some work out of this," nods his rather more famous grandson. For now, at least.

The King of Staten Island is out now on various platforms now

Follow us on Facebook or on Twitter @BBCNewsEnts. If you have a story suggestion email entertainment.news@bbc.co.uk.

Read More