EXCLUSIVE: Kate Beckinsale flashes her underwear under a sheer white dress as she dances the night away on the Sunset Strip in West Hollywood

Kate Beckinsale put on a racy display in her bra and pants on Monday while partying on West Hollywood’s Sunset Strip.

The actress, 50, flashed her blue underwear underneath the sheer white mini dress with fur trim and matching cover-up.

She completed the ensemble with black knee-high boots and carried a huge fan in her hand.

Although she spent most of the night partying in a private room, she took the stage to sing and dance to Jessies Girl at Whiskey a Go Go.

Kate had her brunette locks swept back in a ponytail held in place with a pink bow

It comes after Kate celebrated her 50th birthday in style last month by throwing a raucous party at her Hollywood mansion.

The actress was joined by a slew of celebrity friends who gathered to commemorate the occasion, including Demi Moore, James Marsden, rapper Big Boss Vette and Selling Sunset star Chelsea Lazkani.

Kate looked sensational for her big night, flaunting her incredible figure in a red velvet dress with sexy cut-outs at the waist and a thigh-high slit that flashed her long legs.

To add to the glamour, the mother-of-one slipped on a pair of sky-high platform heels and styled her hair into a ponytail with a big bow headband, revealing a pair of dazzling diamond earrings.

However, just one outfit wasn’t enough for the star, and Kate later changed into a dazzling silver bodysuit that she paired with an extravagant feathered scarf.

As Demi Lovato, TOWIE star Chloe Sims, Vas J Morgan and Jonathan Cheban cheered her on, Kate blew out the candles on her three birthday cakes before heading inside to dance.

While Big Boss Vette performed her hit Pretty Girls Walk, the actress showed off her twerk skills and ripped up the dance floor with her spicy moves.

She shared a slew of snaps from her party in an Instagram post on Monday, writing: “The most amazing birthday continues.. what a party full of love and glitter and the best of people. Thank you to everyone and especially to everyone.’

Kate – who turned 50 on Wednesday – has celebrated her birthday by organizing various events with her loved ones.

Last week she celebrated her milestone birthday with a fun night at a karaoke bar, with the model joining her mom for a rendition of Peggy Sue.

Wow! The actress, 50, flashed her blue underwear underneath the see-through white mini dress with fur trim and matching cover-up

Night Out: She completed the ensemble with black knee-high boots and wore a huge fan at the Whiskey a Go Go bar

Documenting the moment, she told her Instagram followers, “I’ll tell you something. Getting old is great. Thank you from the bottom of my heart for the most magical day full of joy and love and dear dear friends and the strange bird (not me but also me).

“For those who missed the sound of yesterday’s birthday videos, voilà – for those who could have done without hearing my mom and I kill Peggy Sue, tough bananas.”

After the main event, Kate relaxed in loose-fitting pink sweatpants and a graphic tee, later layering over a fun cardigan with “f***” on the back.

It comes on the heels of news that Kate’s ex-husband Len Wiseman has moved in with longtime girlfriend CJ Franco, 32 – eight years after the pair started dating when he split from his actress wife.

“CJ and Len recently took their relationship to the next level by moving in together,” said a source close to the couple.

Len and CJ’s relationship began amid his tumultuous divorce from Kate, whom he married in 2004 and dated in 2015.

Any drama that might have clouded the early days of their romance was far from the couple’s minds this past weekend as they stepped onto a charity comedy show, Models of Comedy, together, seeing every inch of the blissful, cohabiting couple.

CJ, who performed on the stand-up show, and director and filmmaker Len appeared on the red carpet at the Hotel Ziggy prior to the event and, according to one guest, were “incredibly flirty” throughout the night.

During her 15-minute monologue, “Len sat front and center and didn’t take his eyes off CJ. You could see how badly he had been beaten,” the eyewitness added.

Birthday girl! Kate celebrated her 50th birthday in style on Sunday by throwing a raucous party at her Hollywood mansion

Yum: With Demi Lovato, TOWIE star Chloe Sims, Vas J Morgan and Jonathan Cheban cheering her on, Kate blew out the candles on her three birthday cakes

Bunny girl birthday: Kate – who turned 50 on Wednesday – has celebrated her birthday by organizing several events with those close to her

The two lovebirds attended the after party together, where they continued to pack their PDAs as they chatted with friends, including Christine Peake – former British model turned comedian and Hollywood publicist, who hosted and performed on Models of Comedy.

The eyewitness told DailyMail.com that Christine and CJ “stole the show” and were “obviously crowd favorites. “CJ got the audience rolling with a routine that included supporting jokes about her dad being gay,” the source said.

“She told the audience she was going to Las Vegas soon for her dad’s wedding — we’re assuming Len.”

Len’s relationship with CJ came about after his split from Kate, whom he married in 2004 after falling in love on the set of 2003’s Underworld.