The Oscar-winning actor, 58, was photographed backstage at a Bono concert with Ines de Ramon on Sunday.
When they were hanging out with Cindy Crawford and Rande Gerber, who are married.
De Ramon, who works for Anita Ko, separated from her husband, Vampire Diaries star Paul Wesley, in September.
Pitt wore a grey sweater, blue jeans, and a brown hat. de Ramon wore a cropped white top under a patterned jacket, black pants, and boots.
De Ramon, who graduated from Geneva University in 2013, married Wesley in 2019.
A representative for the couple revealed in September 2018 that they had been separated for some time.
"The decision to separate is mutual and occurred five months ago," the rep told PEOPLE.