"Most birthday party guests sent gifts to Jen's house," a source tells PEOPLE

Brad Pitt not only showed up to support his ex-wife Jennifer Aniston as she celebrated her 50th birthday on Feb. 9, but he also sent her a present—as did most of her other celebrity friends who turned up for the star-studded soirée.

“Most birthday party guests sent gifts to Jen’s house,” a source tells PEOPLE. “Brad did too. Her friends are all very generous and creative, and she seemed very excited by all the gifts.”

The source adds that most of Aniston’s friends were also very pleased to see that Pitt, 55, showed up to the bash.

“He was invited, so why shouldn’t he go?” another source says of Aniston’s ex, who was married to the former Friends star between 2000-2005. “He’s single and has no one to answer to. He and Jen spent many important and happy years together. He obviously decided to join her celebration because he wanted to.”

Los Angeles Premiere of Universal Pictures' Film "Along Came Polly"
Credit: Kevin Winter/Getty

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Pitt split from his second wife Angelina Jolie, with whom he shares seven children, in 2016. (Their divorce is still ongoing.) But despite his rocky split from Aniston in 2005, there are no hard feelings or grudges on either side.

The first source says, “Her friends were happy to see Brad at the party. Whatever caused their divorce is long in the past.” An insider told PEOPLE, “Brad and Jen have a very civil relationship.

The bash, which took place at the Sunset Tower Hotel in West Hollywood, was also attended by A-listers like Gwyneth Paltrow (another of Brad Pitt’s exes), Kate Hudson and Demi Moore.