Days earlier, Ben was in France, where he attended the premiere of his latest movie, The Meyerowitz Stories: New and Selected, at the Cannes Film Festival.
Ben has attended many events without Christina over the past few months, including the 2017 Chaplin Award Gala in New York City earlier this month and several Zoolander 2 premieres.
The two have not been photographed together since mid-April, when they took their 15-year-old daughter Ella Stiller to the opening night of the Broadway musical Groundhog Day. Ben and Christine are also parents to 11-year-old son Quinlin.
"With tremendous love and respect for each other, and the 18 years we spent together as a couple, we have made the decision to separate," the couple had said in a joint statement to E! News Friday. "Our priority will continue to be raising our children as devoted parents and the closest of friends. We kindly ask that the media respect our privacy at this time."
Ben and Christine tied the knot in May 2000. They have often starred together in movies, such as Zoolander, Tropic Thunder and Arrested Development.