According to Rocketman, Elton John’s mother, Sheila, was not a warm and fuzzy British matriarch who offered round-the-clock support. In fact, Sheila is scripted as being so cruel to her only son that when Bryce Dallas Howard, who was cast to play the part, first read Lee Hall’s screenplay, the actress was taken aback.

“When I first read the script, I was kind of shocked,” Howard told Vanity Fair—surprised by Sheila’s coldness and the cutting comments she made to her sensitive young son, which shaped the musician’s emotions and anxieties into adulthood. “I questioned [the portrayal]. Like, Hmm, this feels like vilification, and I don’t know if this is accurate.” So the actress did her own investigative work about the woman she would be playing—seeking out people who knew Sheila and were not affiliated with the Dexter Fletcher–directed film. In the end, they corroborated the script’s depiction: “In honestly every single conversation, it was confirmed to me that, yeah—this was a very dysfunctional relationship, and she was a broken woman.”

“Elton was born. . .in Pinner, England—right after World War II,” explained Howard. “The city had gone through so much, and there was still rationing in place, so it was certainly not an easy time. She married Elton's father when Elton was six years old, and they just absolutely hated each other”—a point confirmed by Elton John himself. “They gave every impression of hating each other,” the singer wrote to The Guardian this year. “My dad was strict and remote and had a terrible temper; my mum was argumentative and prone to dark moods. When they were together, all I can remember are icy silences or screaming rows. The rows were usually about me, how I was being brought up.”

And when Sheila discovered that her son was incredibly gifted—able to tap out tunes on the piano as he heard them at just five years old—life did not get any easier. “Elton was a child prodigy, and that was shocking and complex because she did feel that her life was not her own,” said Howard. “A lot of resentment came from that. But it definitely crossed over—the cruelty and the kind of mean persona and, you know, just not showing love, ever. It makes me wonder if she wasn’t well, possibly. It had shifted into a place that was toxic and dangerous.”

Howard was so startled by the behavior she heard about that she reached out to a friend of hers who is a psychiatrist.

“I talked to him about her, because I wondered if there was maybe a personality disorder. Unhappiness is one thing. So is resentfulness. But it was strategic cruelty. She would kind of vacillate between indifference and strategic cruelty, and that’s just—to me, as a parent—I couldn’t quite wrap my mind around that without thinking it was a result of some kind of psychosis.”

Stuart Epps, a British record producer who worked with John in the ’70s, confirmed to the Daily Mail that mother and son, who were 22 years apart in age, had an unusual relationship—acting “more like brother and sister in a way. And [they] fought like that, too.” Of Sheila, he added, “She was pretty outrageous, which is where Elton gets all of that from.” John himself confirmed that his relationship with his mother was a roller coaster: “I was closer to Mum than Dad, but there were long periods when we didn’t speak,” he told The Guardian. “And my childhood is one thing I’m still sensitive about.”

“There were ups and downs, because she was very charismatic and witty—very funny and cutting,” said Howard. “She would say the things that people are thinking but not saying. That’s a little delicious, up to a point.” Howard thinks that John’s wicked sense of humor is inherited from Sheila. “But he’s a very, very, sensitive, emotional person,” Howard added. “And it didn’t seem that that’s how Sheila was herself.”

Despite Sheila’s coldness, Elton supported his mother financially once he found success—even hiring her to watch over his Virginia Water mansion while he was on tour. According to the Daily Mail, “he would call her every Saturday so that she could fill him in on the football results.” But John, as shown in Rocketman, was also prone to mood swings and temper tantrums. “I went through all that with him,” Sheila later confirmed. Epps even recalled how Elton fired his own mother at one point: “You know Elton, he fires everyone,” Epps explained. “He said to her: ‘You are fired as my mother!’ He was in such a temper. It must have been 40 years ago.”

There were other lows in their relationship as well—the most widely reported being an eight-year estrangement that Sheila said was caused by Elton’s husband, David Furnish. While John offered minimal public commentary about his mother out of respect for her privacy, Sheila took a different approach with the press. In 2015, seven years into her estrangement from her son, Sheila hired an Elton John impersonator for her 90th birthday—and then gave a blistering interview to the Daily Mail. Speaking about Elton, Sheila said, “He had always been very kind to me until he got with David Furnish.” She blamed Furnish for driving a wedge between John and his longtime personal assistant Bob Halley. “It’s pretty obvious if anyone thinks about it. Elton didn’t even fall out with Bob [Halley] really. The relationship ended abruptly,” Sheila said. “Everybody was got rid of all of a sudden. That’s what happened, and everybody has gone—me included. . . .and we know who is behind that!”

As if those remarks were not hurtful enough, Sheila remained friends with John’s ex John Reid, and described Halley as “like a son to me. He has always been marvelous to me and he lives nearby and keeps an eye on me.’ [...] [Elton] told me I thought more of Bob Halley than I did of my own son. And to that I said to him, ‘And you think more of that fucking thing you married, than your own mother.’ Those were the last words I spoke to him.”

When pressed to comment on his mother during this period, John simply said, “I don’t hate her, but I don’t want her in my life.”

But Sheila had no qualms about getting catty with press—making digs about her son’s ability to be loved that echo sentiments the character of Sheila shares in Rocketman. “At the beginning of [Elton and David’s] friendship I was glad he had found someone to settle with after so much disruption with all the various boyfriends coming and going,” Sheila said. “They would get what they wanted out of him, they’d get their houses and whatever they wanted and then they wouldn’t love him any more. And then I would be dragged into it…. We had all this to put up with. But you are there for him because he's your son.”

She also accused Furnish of banning her from family photos taken at the couple’s 2005 civil partnership ceremony because she did not wear a hat as instructed. (“That didn’t go down well with Furnish because he wanted it to be the Wedding of the Year,” Sheila snarked.) She also claimed that John refused to visit his stepfather, Fred Farebrother, in the hospital in 2007 before he died. A fiery woman, even at 90, Sheila told press, “I’d like to give Furnish a punch right on the bloody earhole! If I had the chance, I'd do it…. I’ve had all the upset and crying and the worrying and the nastiness.”

After eight years of estrangement, John told The Daily Mirror that he and his mother had finally reconciled. “I have always shied away from speaking publicly about our relationship,” he said. “However, I can say that we are now back in touch and have been so since my mother’s 90th birthday.”

A year after the reconciliation, Sheila died, leaving John devastated. “I saw her a week before she died and thought, ‘God, she’s pretty feisty, she’s going to last for a few months,’” John later told The Sun. “A week later she was dead. It really shook me.” On Instagram, the musician further expressed his sorrow. “So sad to say that my mother passed away this morning,” he wrote. “I only saw her last Monday and I am in shock. Travel safe Mum. Thank-you for everything. I will miss you so much. Love, Elton.”

But Sheila dealt her son another blow posthumously. In her will, which was reportedly changed less than a month before her death, she only left John two urns, and “my photographs of mother in uniform and grandfather in uniform.” Sheila bequeathed a sizable percentage of her £534,000 fortune to Halley—whom John suspected Sheila preferred as a son. “Sir Elton is worth [$414 million], but it’s not the money that matters,” a source told The Sun. “It very much looks like Sheila was determined to make one final point to her son in her will.”

Even so, John, dutiful son that he was, oversaw his mother’s funeral. “Dear Mum, Today’s funeral was perfect,” the musician wrote on Instagram. “Having the service in the family chapel and attended by your brother and sister brought us all comfort. Having the service where Nan lived out her final days brought you and your Mother back together again. Tomorrow your friends will gather separately to say their good byes. I’ve chosen all the music so everything will be just right. Thank-you for bringing me into the world and for all that you have done for me. Love, Elton #RIP.”

Given John’s rocky relationship with Sheila, Howard was understandably nervous to see how the legend himself would react to her portrayal of his mother at Rocketman’s Cannes Film Festival premiere.

But when the lights went up and the standing ovation was in full swing, the real-life Elton John approached the actress with a single-word review: “Bitch.”

“It was just the one word,” laughed Howard when she spoke to Vanity Fair. “It was good feedback.”