Silverstone, 34, and her rocker husband Christopher Jarecki welcomed Bear Blu Jarecki on Thursday, just in time for Mother's Day.
Silverstone's rep released this statement: "Mom and Dad are completely in love" with their "beautiful baby boy."
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The couple wed in 2005 after eight years of dating.
Baby Bear is an apt name for the tot, seeing as how vegan Silverstone is a longtime animal rights campaigner.
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