January Jones caused a stir in Las Vegas recently
The Mad Men beauty, who turned 39 on January 5, shared a number of snaps of her seemingly raucous night out with her 466,000 Instagram followers.
The actress flashed her bra while her cleavage took centre-stage during her party at Sin City's CliQue Bar & Lounge.
Wearing her tresses down in a voluminous style, January turned heads in a super low-cut black dress, which featured a white star print throughout.
The film star couldn't resist giving fans a glimpse of her 'do, however the only thing people were talking about was her ample chest.
January Jones shared a number of snaps of her 39th birthday bash
January Jones happily flashed plenty of cleavage
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Okay, now you're just trying to make my heart stop January Jones…
"@thecliquelv bday drinks! Thanks for hosting us,"(sic) January captioned the first of three uploads.
Other users were quick to compliment the blonde, with one person writing: "Okay; now you're just trying to make my heart stop…"
Two others agreed: "Please marry me," and: "Yabadabadooo!" while another quipped: "Look at those girls!"
January Jones wowed in a black star print dress
January Jones is no stranger to flashing the flesh
January's trip comes just days after she said she had "no regrets" about raising her son without a father.
Following Xander's birth in September 2011, she has refused to reveal who his dad is.
She told the February issue of Red magazine: "I don't believe in regret. I just try to be a better person. Try to be a better mum."