Rose Byrne Shows Off Tiny Waist Two Months After Giving Birth

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Just two months after giving birth to son Rocco Robin, Rose Byrne is running a clinic on how to drop the baby weight!

The 36-year-old actress has been all over New York this week, flaunting her astonishingly tiny waist.

WATCH: Rose Byrne and Bobby Cannavale Welcome Their First Child

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Always the epitome of class and feminine sophistication, Byrne was a vision in a mosaic-printed frock when she attended a screening of The Meddler at Crosby Street Theater on Monday. She complemented her ensemble with a pair of grey pumps and a snakeskin belt.

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On Tuesday, she met up with her Meddler co-star Susan Sarandon to discuss the film during an AOL Build Speaker Series session at AOL Studios in New York.

Before fielding questions, Byrne posed in a monochrome frock with a black belt and green pumps.

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Rocco marked Byrne's first child with longtime partner Bobby Cannavale.

Cannavale announced the arrival of his son on The Late Show With Stephen Colbert on Feb. 5.

WATCH: 9 Celebrity Babies Due in 2016

"I'm so tired. I think I've gained 28 pounds since Monday," the 45-year-old Vinyl actor joked at the time. "I'm not kidding, this jacket used to fit so well but I've been eating so much!"

Fortunately for Cannavale, he can pick up weight-loss tips from Byrne, who clearly knows how to shed pounds the right way.