Jennifer Aniston is friendly with both her ex-husbands, with Justin Theroux a guest at her Thanksgiving party last month and Brad Pitt scoring one of the most coveted Hollywood invitations of the year.

Aniston’s big thing has long been her intimate Christmas tree-trimming party, when she throws open the four-metre front door of her 1970s Bel Air mansion and welcomes her BFFs with tinsel and tequila.

On December 14, one of the first to rock up – beating other A-listers including Gwyneth Paltrow, Kate Hudson and Jimmy Kimmel – was Pitt, 55, whose early gifts to himself this festive season include Golden Globe and SAG Award nominations for Once Upon A Time in Hollywood.

“The annual tree trimming party is always Jen’s favourite to host,” a source told People.

“She loves Christmas. As usual, a large group of friends attended.”

Aniston and Pitt were inseparable at the 2004 Emmy Awards. Photo: Getty

The actor, who was married to Aniston from 2000 until 2005, arrived at her place “a little after 7pm”, a witness told Entertainment Tonight.

“He was among the first to arrive and the second to last guest to leave around 11pm,” the source said.

“He was dressed casually in a dark bomber jacket with a cap on. He arrived with his long-time security guard who waited for him with his car and saw him out.”

While the soiree was a “pretty low-key, casual affair”, the source said it was also “very festive” and “just a gathering of close friends to celebrate the holidays”.

The inclusion of Pitt in the “close friends” category at Christmas time comes after he was also on the list for the Morning Wars star’s 50th birthday party at the Sunset Tower Hotel in Los Angeles.

That was because the exes have a “very civil relationship”, a different source told People at the time, while another said that Aniston consulted her girlfriends about whether or not to invite the Ad Astra leading man.

“He would not have been asked to come if that weren’t the case. It was a big night for Jen.

“The important people in her life gathered to celebrate with her. Brad fits into that group, and it was natural that he would want to come.”

Since then, Aniston and Pitt have been “in touch a few times”, according to the first source, “and are keeping it friendly”.

For the first time in many years, they may share a red carpet or two during awards seasons, with Aniston’s role as a breakfast TV host in Morning Wars scoring a nod for January 6’s Golden Globes.

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Aniston and Pitt broke up when he fell for his Mr and Mrs Smith co-star Angelina Jolie.

They shared six kids and spent 12 years together before a sudden and acrimonious split after an incident on a private jet flight in 2016.

Aniston and Theroux, 48, took a posse of friends on their Bora Bora honeymoon after marrying in August 2015, but “lovingly” – the actor’s description to the New York Times – split at the end of 2017.

“It was heartbreaking,” Theroux said.

Still, some diehard romantics saw it as an opportunity for Brad and Jen to reunite but that idea was a bust, according to the man himself.

Pitt – who told the Los Angeles Times “none” of the stories linking him to MIT professor Neri Oxman, jewellery designer Sat Hari Khalsa or actor Alia Shawkat are true – laughed in May when a photographer asked him one question “everyone wants to know”.

Is he getting back with Aniston?

“Oh my God,” Pitt said in a video shared by Entertainment Tonight, before hopping in his car and telling the paparazzo, “Alright, have a good one.”