No official word yet from Fox, Green or their reps.
The couple, who tied the knot in June 2010, have admitted to at least looking forward to starting a family.
"I want at least two, probably three kids," Fox said in the April issue of Cosmopolitan. "I've always been maternal."
This will be the second child for Green, who has a 10-year-old son with ex Vanessa Marcil.