“Brad and Jen have a very civil relationship,” a source tells PEOPLE in this week’s issue. “He would not have been asked to come if that weren’t the case. It was a big night for Jen.”
Aniston spent Saturday night at the Sunset Tower Hotel in Los Angeles to ring in the milestone year. Pals like George and Amal Clooney, Ellen DeGeneres, Laura Dern, Robert Downey Jr., Kate Hudson,Demi Moore, Gwyneth Paltrow, Keith Richards, Barbara Streisand andReese Witherspoonwere all in attendance to help Aniston celebrate.
Kate Hudson/Instagram

HerFriendscostars Courteney Cox and Lisa Kudrow were also among the partygoers, as were Aniston’sex-boyfriend John Mayer, his exKaty Perryand the pop star’s current boyfriend, Orlando Bloom.
Chris Polk/FilmMagic

“The important people in her life gathered to celebrate with her,” the insider says. “Brad fits into that group, and it was natural that he would want to come.”
RELATED VIDEO:Jennifer AnistonSays Her Marriages toBrad Pittand Justin Theroux Were ‘Very Successful’
Thoughthe pair— who announced their split in January 2005 following four years of marriage — embraced atAniston’s birthday bash, the actress “didn’t really pay any special attention to Brad,”another source adds. “They hugged and chatted for a bit, but Jen was busy making sure all of her other guests had an amazing time.”
Aniston also received some birthday love from another ex-husband:Justin Theroux. TheLeftoversactor, 47,posted a pictureof Aniston on Instagram on Monday, with the caption, “Happy Birthday to this fierce Woman. Fiercely loving. Fiercely kind. ….and fiercely funny.”
Theroux and Anistonsplit in early 2018, while Pitt, 55, and his most recent ex-wifeAngelina Joliedivorced in 2016.
source: people.com