Megan Fox and Brian Austin Green: Baby on Board!

Talk about one hot mama! Star has exclusively learned that bombshell Megan Fox, 25, is expecting her first child with her husband of nearly two years, Brian Austin Green, 38.

"They just found out and are incredibly excited," says a source, who reveals that the pregnancy was unexpected. "It's still early, so they are only telling close friends and family members."

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But the couple are already eagerly running through lists of baby names, and they are also considering moving to larger digs to raise their new little one and Brian's 10-year-old, Kassius, from a previous relationship.

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"Megan has become a great stepmom, and Brian knows she'll be wonderful with the baby," says the source. "She has really grown in the past couple of years."