Brody Jenner and girlfriend Kaitlynn Carter attend Reggie Bush's wedding on July 12. Credit: Courtesy of Brody Jenner

Brody Jenner may have made a major party foul. The Hills alum, who was noticeably absent from stepsister Kim Kardashian's wedding to Kanye West in May, attended the nuptials of her ex-boyfriend Reggie Bush on Saturday, July 12. 

Jenner Instagrammed several shots at the California ceremony with his girlfriend Kaitlynn Carter. A source told Us back in May that Carter's lack of invitation was what prompted Jenner to skip Kardashian's nuptials in Florence, Italy. 

The pair have been dating for about nine months, and posed with NFL star Bush and his new bride Lilit Avagyan in a photo posted in Instagram. 

"Congrats @reggiebush !!! #bushwedding," Jenner captioned the photo.

A source tells Us Weekly, "Brody and Reggie are really good friends. He invited him months ago with a guest. In terms of Kim, one has nothing to do with the other." 

Bush dated Kardashian on-and-off for several years, but finally split in March 2010.