The Oscar winner, 55, arrived outside the West Hollywood hotel in a big black car. Pitt, who was wearing a cap, was then seen alongside his bodyguard, walking inside as paparazzi yelled his name.
He wasn’t the only one of Aniston’s exes making a surprise appearance — John Mayer was also in attendance.
And making for an even more interesting evening, Pitt’s ex-fiancée Gwyneth Paltrow was also at the party, as was Mayer’s ex-girlfriend Katy Perry, who arrived on a motorcycle with current boyfriend Orlando Bloom.
As Us Weekly previously reported, Theroux found love notes that the Friends alum had saved from her time with Pitt. “He stumbled upon old Post-it notes Brad had written,” a source told Us last year. “Sweet little Post-its like, ‘You looked nice tonight’ or ‘Miss you already.’”
The source added that while the Dumplin’ actress assured her husband that the notes “weren’t a big deal,” Theroux “wasn’t thrilled … Justin had moments of insecurity like that.”
Aniston told Elle in an interview in December that she considered her two marriages to have “been very successful.”
“When they came to an end, it was a choice that was made because we chose to be happy, and sometimes happiness didn’t exist within that arrangement anymore.”
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