HOLLYWOOD, Calif. — James Van Der Beek is expecting a baby girl with girlfriend Kimberly Brook, the couple has revealed.

"We're so excited to announce we are expecting a girl!" Brook, who is due in the fall, tells People magazine. "We are thinking and taking suggestions for names, but we have no idea [what to call her] right now."

Van Der Beek, who announced the pregnancy on Twitter in April, said his girlfriend hasn't surprised him too much as they've prepared for parenthood.

"When the mood swings happened, they were so textbook, I almost had to laugh," he explained. "The hard part was stifling the laughter, like, 'Oh, my god, I can't believe this is happening — this is just like the book said.' She's so amazing, I kind of thought she'd be immune to them."

Van Der Beek and Brook have been dating since last summer.