"She's working, so it's just going to be me and the boys hanging," he said, referring to Sasha and Kai, his two sons with the actress.
Watts is currently in Thailand, where she is filming "The Impossible," a movie based on the 2004 tsunami that devastated that country, starring Ewan McGregor.
"We'll figure out something," Schreiber said. "I'll send her some flowers, or whatever they've got in Thailand."
Schreiber was at Cipriani Wednesday night to celebrate the 25th anniversary of amfAR, The Foundation for AIDS Research. The black-tie gala benefit, which also served as the unofficial kick-off to New York Fashion Week, honored President Bill Clinton, Elizabeth Taylor, and fashion designer Diane von Furstenberg for the extraordinary contributions they've made for the fight against AIDS.
Schreiber, who said he's "kept up" with the chairty for ten years, praised it for being "effective."
"I think amfAR has made great inroads," he said. "And I think the fight [against AIDS] has broadened. It's not just at home any more."
"That's one of the things I like about amfAR as a charity - they respond to the international need," he added.
Though Schreiber is recognizable from the work he's done in movies, he is perhaps better known for the many roles he's played on stage. Most recently, he starred opposite Scarlett Johansson in last year's Broadway revival of "A View From The Bridge."
Niteside asked Schreiber if he wanted to return to the theater soon.
"I hope so," he said, "but there's nothing planned yet."