Ravishing in retro! Jennifer Lopez gives a glimpse of toned legs in monochrome dress and thigh-high boots while out to dinner

Jennifer Lopez worked up an appetite that afternoon sweating it out on set of American Idol.

Just hours later the 45-year-old singer-actress transformed into Sixties siren as she hit up STK Steakhouse in West Hollywood, California for dinner on Wednesday night.

Jennifer looked sleek in a chic retro-style frock that featured one side in white and the rest in black while separated by a length of bronze buttons.

Sixties siren: Jennifer Lopez impressed in a retro-style two-toned mini-dress and thigh-high boots while heading to dinner at STK Steakhouse in West Hollywood, CA on Wednesday 

The hem fluttered to mid-thigh region, exposing her dance-toned limbs to the point where her tall, black suede boots took over.

Jennifer's thigh-high boots were the sexy twist to an already eye-catching ensemble.

As if that wasn't enough, J-Lo's long and sharp, pastel blue nails drove the point home.

Her lustrous hair was parted centre and fell in continuous waves to her trim waistline.

Monochrome magic: J-Lo's outfit featured a side panel in white and the rest in black while separated by a length of bronze buttons

Mirage: The 45-year-old singer-actress was perfectly coiffed and made-up with shimmery blue shadow

  Working up an appetite: She had spent the better part of the afternoon rehearsing on set of American Idol ahead of the show's live two-hour show on Thursday

Jennifer was perfectly made-up with shimmery light blue eye shadow, a blend of rouge and neutral lip gloss as she stepped lightly to the eatery's entrance while clutching her iPhone.

Earlier in the day, J-Lo showed a different, more casual side as she headed to the set of American Idol.

At that time, she was dressed down in star-spangled grey track trousers, white top and wedge-heeled trainers.

Driving home the point: Jennifer displayed pointy long nails painted a pastel blue along with a sparkly ring to match her glittery eye shadow

Casual in her own way: The American Idol judge went to work on the LA set of the Fox talent show in track trousers and a fur wrap to warm up in

As the day was overcast, she'd thrown on a fur wrap to warm herself against the balmy chill while her hair was haphazardly piled into a bun on top of her head.

On Monday, the on-the-go star released a video for her Jennifer Lopez Collection For Endless Jewelry.

In it she promised: 'My new exclusive Endless Jewelry line is designed to be fun, festive and elegant... I hope you enjoy them, the possibilities are endless.'

'The possibilities are endless': The star released a promotional video for her Jennifer Lopez Collection for Endless Jewelry on Monday

Special appearance: J-Lo will also lip-sync her song Booty with Anna Kendrick on Spike TV's new show Lip Sync Battle set to premiere on April 2

That same day, Jennifer celebrated by posting a fun snap to Instagram that showed her hanging out with best friend Leah Remini and power producer Elaine Goldsmith-Thomas.

'Girl time!' the mother-of-two captioned the image.

J-Lo and the producer are working on their next joint effort, Shades Of Blue, a new police TV series that will star Lopez.

The show, which will debut in fall 2015, has a 13-episode commitment and also stars Drea de Matteo, Ray Liotta and Vincent Laresca.

It shoots in New York and is about a single mom who works undercover for the FBI on an anti-corruption task force.