The 27-year-old revealed earlier this month that she and husband Ryan Reynolds, 37, are expecting their fist child, via her lifestyle blog Preserve.
Uploading a snap onto the site showing her cradling her bump, the Gossip Girl actress wrote: "The entire next month will be sprinkled with highlight for women in this exciting chapter of their lives. Congratulations to all the expecting mothers out there."
Attending the God's Love We Deliver, Golden Heart Awards last night in New York, a happy Blake proudly showed off her baby bump for photographers.
She wore a stunning glittering champagne gown, kept her blonde hair natural and flowing and complimented the look with sparkly drop earrings and rings.
Speaking to E! news, Blake confessed that she's always felt like a mother as she comes from a big family.
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She said: "I came from a big family – a big family of Southerners. I feel like I've always sorta… I'm the youngest of five, so I never raised any siblings below me, but I'm always the person who's taking everyone else's kid and putting them on my hip, so I've kinda always been a mama. So we'll see."
Blake and Ryan met in 2010 on the set of their film The Green Lantern, and married in 2012 in an intimate ceremony attended by close friends and family.