She may be in the best shape of her life.

And Jennifer Lopez couldn’t help but flaunt her fabulous figure during her milestone day.

The multifaceted actress rocked an eye-popping number while celebrating her 46th birthday on Friday night.

Still stunning: Jennifer Lopez celebrated her 46th birthday in a rather racy ensemble on Friday night

Iconic: She flashed her famous backside in the dress with a sheer detailing at the popular New York hotspot 1Oak in Southampton

J-Lo could be seen partying it up in the revealing frock during the celebration at the popular New York hotspot 1Oak in Southampton where guests enjoyed gluten-free Summer cocktails by CÎROC Vodka.

The Waiting For Tonight singer scintillated in the cleavage-bearing clinging black dress which showed off her best assets.

The frock featured cut outs along the side and just under the chest in addition to a mesh detailing running down to side which no doubt accentuated her iconic backside.

Curvaceous: J-Lo gave a sultry stare as she rocked the sexy clinging black dress which showed off her cleavage and had cut-outs on the side

Cheeky: The singer and actress was not shy about showing off her fabulous figure in her forties

She wore her highlighted brunette tresses down flowing over her shoulders as her skin looked flawless for being in her forties with natural, complimentary make-up on it.

She could also be seen rocking the racy number in Instagram pictures posted by friends Fat Joe and Khloe Kardashian’s ex French Montana.

In the snap shared by 30-year-old rapper French, he and Fat Joe flank the American Idol judge while they are joined by singer and author Thalía.

In another picture posted by 44-year-old rapper – real name Joseph Cartagena – she is joined by Thalía and Joe’s wife Lorena Cartegena as they all cuddle up for a snap together.

Party people: Jennifer partied the night away with famous friends including (pictured from left to right): French Montana, Fat Joe and Thalia

Three’s a crowd: Fat Joe’s wife Lorena Cartegena and Thalia also flanked J-Lo in another snap

Fantastic four: Khloe Kardashian’s ex French, Thalia, Joe and Lorena certainly seemed to have a blast

Hanging out: Earlier in the day Joe posted this image with the birthday girl J-Lo and Loren Ridinger

Moving and grooving: French shared this snap of him dancing with Jennifer and the caption: ‘Happy bday to my big sis @jlo #southbronx’

Assistance is needed: Jennifer was helped out of the chauffeured vehicle by Casper Smart

Escort: JLo was pleased to be escorted to the festivities by her much younger boyfriend

Hang on: The couple linked hands as they strolled to the venue

Right behind you: Casper led the way while Jennifer followed

Earlier that day, J-Lo commemorated the special day by sharing a throwback of herself celebrating her birthday as a toddler.

Clad in a crimson dress, the photo shows a giddy young Jen smiling and posing in front of her white birthday cake with pink frosting flowers.

The mother-of-two turned singer captioned the archived snap with a simple, ‘#TBT.’

Side view: JLo gave another glimpse of her voluptuous figure

Diva in spotlight: The American Idol judge kept her head down while walking past the crowd of well-wishers

Famous booty: Jennifer showed off more of that famous derriere

All-star turn out: French Montana was among the party-goers

Party in the limo: Jennifer and her pals were having a great time

Earlier on…: Before the party, Jennifer and Casper stepped out to celebrate her birthday with family and friends in Sag Harbor on the private yacht Utopia 3

Summer brights: The leggy lovely showed off her shapely pins in a cute brightly-coloured pair of shorts and matching crop top, proving that her showstopping fashion choices aren’t just for after dark

Mwah! The cute couple seemed to be sharing an intimate moment as Casper drove them to her daytime celebration

Later in the day, J-Lo posted another photo of what appears to be Marilyn Monroe blowing a bubble gum bubble with the words, ‘It’s my birthday!!’ scrawled across her face.

Also showing support via social media for the Booty singer on her big day was her on-again off-again beau, Casper Smart.

The snap shows a selfie of the 28-year-old dancer with a wiry beard smiling and lying in bed.

Posted on Thursday, Casper captioned the photo: ‘Smiling cause do you know what tmrw is???’

Celebratory throwback: On the same day Jennifer shared a throwback photo of herself celebrating her birthday with she was a toddler

Then and now: The video for Jenny From The Block (left) premiered in 2002 but J-Lo present day (right) hasn’t changed a bit

In the spirit: Lopez also shared a photo of what appeared to be Marilyn Monroe blowing a bubble with gum as the words ‘It’s My Birthday!!’ were scrawled across the front

Getting excited: On Thursday, J-Lo’s on-again off-again beau Casper Smart took to Instagram to share his excitement for the big day. He captioned the snap: ‘Smiling cause do you know what tmrw is???’