Elton John held nothing back when it came to his mother Sheila Farebrother.

In an excerpt, published by UK’s Daily Mail, from the singer’s upcoming memoir titled “Me,” the legendary singer recalled how he was gearing up to celebrate his relationship with longtime partner David Furnish with a civil partnership. It was Dec. 21, 2005 — the same day when civil partnerships became legal in England.

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“I was as happy as I could ever remember being,” recalled the 72-year-old. “And that was the moment my mother turned up, in character as a raving sociopath.”

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After an adoption effort fell through, the couple turned to a gestational carrier in 2010 to give birth to their son Zachary. (Reuters)

The British artist claimed he knew something was wrong when Farebrother and his stepfather arrived at his Old Windsor home. The couple refused to leave the car.

“Despite various entreaties to come into my house, they just sat there, stony-face,” wrote the British artist. “There, Mum announced she wouldn’t be joining the convoy of cars setting off for Windsor nor would she be coming to the private lunch afterward. Oh great. The most important day of my life and one of Mum’s moods appeared to be upon us.”

John said he was all too familiar with his mother’s severe mood swings, which impacted their relationship since his childhood. He dubbed her the “Cecil B. DeMille of bad moods, the Tolstoy of taking of huff.”

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Sir Elton John and his mother Sheila Farebrother during The Fifth Annual White Tie & Tiara Ball to Benefit the Elton John Aids Foundation in Association with Chopard — Dinner at Elton John Residence in Windsor, England, United Kingdom. (Photo by KMazur/WireImage/Getty)

“She didn’t — couldn’t spoil the day, of course,” recalled John about his civil partnership ceremony. “But in fairness to Mum, she absolutely gave it her best shot.”

John said he remained on his best behavior and avoided confronting Farebrother. He was determined to prevent a public scandal on what should have been his special day.

But things only continued to deteriorate from there.

“When David and I exchanged our vows, she started talking very loudly, over the top of us, rattling on about how she didn’t like the venue and couldn’t imagine getting married in a place like this,” John said. “When the time came for the witnesses to sign the license, she signed her name, snapped: ‘It’s done, then,’ slammed the pen down and storm off.”

Elton John leaves St George's Chapel at Windsor Castle after the wedding of Meghan Markle and Prince Harry. Saturday May 19, 2018.  Chris Radburn/Pool via REUTERS - RC12047C70F0

Elton John leaves St George's Chapel at Windsor Castle after the wedding of Meghan Markle and Prince Harry. Saturday May 19, 2018. (Chris Radburn/Pool via REUTERS)

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According to John, Farebrother’s mood didn’t improve at the reception. Instead, she complained about her seating placement, declaring, “You might as well have stuck me in Siberia,” as well as snapping back at anyone who approached her.

Sharon Osbourne, a guest at the reception, whispered to John in his ear, “I know she’s your mum, but I want to kill her.”

John also claimed that Farebrother had previously called Furnish’s parents in an attempt to stop the ceremony, believing it would spoil her son’s career. The revelation confused John, who always felt his mother had been supportive of his sexuality.

Musician Elton John (L) and his husband David Furnish arrive at the 2014 Elton John AIDS Foundation Oscar Party in West Hollywood, California March 2, 2014. REUTERS/Gus Ruelas (UNITED STATES TAGS: ENTERTAINMENT) (OSCARS-PARTIES) - RTR3FXFZ

Elton John (L) and David Furnish arrive at the 2014 Elton John AIDS Foundation Oscar Party in West Hollywood, California. (Reuters)

“She has never been homophobic,” he wrote. “As ever, I think the real problem was that she hated anyone being closer to me than she was… She couldn’t cope with the tough of the umbilical cord finally being cut and she didn’t care about anything else, including the fact that I was finally happy.”

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John’s relationship with Farebrother didn’t improve after the civil ceremony. After he and Furnish, now 56, welcomed their first son Zachary in 2012, John said that he “started actively avoiding” Farebrother and they “weren’t speaking at all.”

The remains of their relationship reached a screeching halt when John fired his longtime assistant Bob Halley, who was close to Farebrother. John claimed his mother was “livid” when she heard the news and said Halley had always been more of a son to her than John.

“And that’s when she said: ‘You care more about that f---ing thing you married than your own mother,’” wrote John. “We didn’t speak for seven years after that phone call.”

Despite the spat, John said he continued to support his mother financially. However, mother and son remained estranged.

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“It was sad, but I didn’t want her in my life anymore,” he explained. “I didn’t invite her to the ceremony when the law on gay partnerships changed again, and David and I got married in 2014.”

Singer Elton John, founder of the Elton John AIDS Foundation, pauses as he testifies before a Senate Appropriations State, Foreign Operations and Related Programs Subcommittee hearing on global health problems in Washington May 6, 2015. REUTERS/Carlos Barria - GF10000085958

Elton John announced his mother had died. (Reuters)

He claimed Farebrother then started selling gifts he gave her, including platinum albums he had engraved just for her. She also celebrated her 90th birthday in 2015 with an Elton John tribute artist instead of her own son.

In 2017, John reconnected with Farebrother when he learned she was seriously ill. When he told her he loved her, he claimed Farebrother replied, “I love you, too. But I don’t like you at all.”

That same year, Farebrother died of an undisclosed illness. John made the announcement on social media.

“So sad to say that my mother passed away this morning,” he tweeted at the time. “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.”

In his autobiography, John said that he finally broke down while giving her eulogy at the funeral service.

“I missed the person I was describing terribly, but I’d started missing her decades before she died,” he wrote.