Apparently she told her husband, the "Transformers" actor Josh Duhamel, the news at an LA Dodgers game.
He's been wanting a baby since they married earlier this year, but Fergie hadn't wanted to put her career on hold. Now she's reportedly changed her mind.
A source told the National Enquirer magazine: "She turned to him and told him she wanted a baby to make their lives complete.
"She says pregnancy will be a crash course in cleaning up her act."
Oh good. What a great reason to have a baby - to clean up your act. "Why did you have me, Mummy?" - "So I wouldn't be tempted to get back on the crystal meth, darling..."
Meanwhile, Catatonia singer and I'm a Celebrity star Cerys Matthews is expecting her third child.
The singer, who is 40, is due to have the baby in January with her boyfriend and manager Steve Abbott, 49.
They had kept the pregnancy a secret up until now because they were concerned there could be complications due to her age. But she's now been given the all-clear.
Cerys has been with Steve since February and already has two children with her ex-husband Seth Riddle.
They're called Glenys Pearl y-Felin and Johnny Tupelo Jones. Uh-oh - daft celebrity baby names alert. Watch this space.On Coronation Street, real life and soap life are colliding, but not particularly successfully.
Samia Smith's character Maria has just given birth, but Samia herself is still seven months pregnant. Whoops.
The actress reckons she needs a bigger handbag to cover up her bump.
She said: "I'm using my handbag a lot, put it that way. It needs to be a bit bigger, though - I might have to go out and buy a new one. The clothes aren't working as well as I thought they would!"Source: AOL News Source: The Sun Source: AOL News