News of the Australian actress' pregnancy was released Sunday by fashion-design firm Escada, which created the yellow gown Watts wore to the Academy Awards.
The dress "set off her most precious new asset, the baby she is expecting with long time boyfriend Liev Schreiber," the company's press release read.
Schreiber confirmed the news on "Late Night with Conan O'Brien" Monday, saying, "Yes, I'm going to be a dad."
Watts, 38, and Schreiber, 39, co-starred in last year's "The Painted Veil."
He's currently in rehearsals for a Broadway production of "Talk Radio," slated to open March 11.