The 35-year-old actress is yet to confirm the news but an inside source claims that the couple, who got married in 2002, are 'thrilled' by the pregnancy, reported People magazine.
"She and Freddie are thrilled. They love their little girl more than anything in the world and know that love will only multiply. She is such a fantastic mom; it is just great news," a source said.
Gellar first met Prinze Jr in 1996 when filming "I Know What You Did Last Summer". They began dating three years later before tying the knot in 2002.
The pair, who also worked together in 2002's "Scooby-Doo" and its 2007 sequel "Scooby-Doo 2: Monsters Unleashed", welcomed their first daughter Charlotte Grace in September 2009. PTI JCH