The 38-year-old actress has been dating clothing designer Jason Bleick for the past year after meeting while working alongside one another on the EVER fashion line. The pair are said to be "ecstatic" about their impending new arrival.
After her representative confirmed the news to People magazine, a friend of the Hellboy star said: "They are ecstatic. They couldn't be happier."
Prior to meeting Jason, the brunette beauty - who was married to musician Ahmet Zappa for two years - admitted while she was enjoying spending time with her girlfriends, she was still on the lookout for a companion
She said: "I've just been reconnecting with my friends. I want someone who makes me feel good, if you know what I mean!"
Although Selma has been spotted wearing a ring on her engagement finger in recent weeks, she has admitted she had "little faith" she'd ever find her soulmate.
She explained: "I have very little faith that I'll ever find someone. I've had some bad luck and I've made some bad choices - not in men, but in how I've chosen to deal with relationships."