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.

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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