Christina Aguilera delivered a memorable performance on Wednesday in New York City with a special guest for her fans during her Liberation Tour stop.

The 37-year-old pop star was joined by Lil' Kim, 44, onstage at Radio City Music Hall for a rare performance of their 2001 hit cover Lady Marmalade.

The cameo got the sold-out crowd that included former President Bill Clinton, 72, and his wife Hillary, 70, buzzing with excitement.

Sold out: Christina Aguilera gave her fans a concert to remember while performing on Wednesday at Radio City Music Hall in New York City

Christina changed into a number of outfits while performing in NYC with all the ensembles boasting phenomenally sexy feels.

She got down while wearing a white dress with over-the-knee matching boots and a corseted top to help boost her eye-popping cleavage.

Christina also stood tall in a black and red leather outfit which paid homage to her legendary chaps in the racy and groundbreaking Dirrty video 2002.

She later looked divine in a white dress with high shoulders and a plunging neckline.

Rare performance: Lil' Kim joined Christina for a rare live performance of Lady Marmalade

Backstage pass: Former US President Bill Clinton and wife Hillary met with Christina backstage

Multiple outfits: The 37-year-old pop star wore multiple outfits during her sold-out concert including a homage to the iconic chaps worn during the Dirrty era

White dress: Christina stunned in a white dress with high shoulders and plunging neckline

The mother-of-two also changed in a red kimono for a stretch of her concert while going make-up free.

Christina also graced the stage in a wide red dress and a stylish black jumpsuit.

The Liberation Tour concert also featured a marriage proposal that occurred onstage as Christina looked on.

Kimono style: She also wore a red kimono-style dress while going barefoot

Fan favorite: The singer is on her fifth concert tour that started last month in Florida

Hit songs: The pop star belted out her hits including Genie In A Bottle

Red dress: Christina wore a wide red dress on the stage

Lady in black: The Beautiful singer looked stylish in a black jumpsuit

Christina, Lil' Kim, Mýa and Pink teamed up for the 2001 version of Lady Marmalade that was produced for the Moulin Rouge! soundtrack.

Lady Marmalade reached the top spot on the Billboard Hot 100 chart and the UK Singles Chart.

Christina and Lil' Kim famously performed the song on stage at the 2002 Grammy Awards along with Mýa and Pink.

Wedding proposal: The concert also featured a marriage proposal

Popular song: Lady Marmalade reached the top of the charts in the US and UK

Special guest: Lil' Kim joined Christina for a live performance of Lady Marmalade

Wild crowd: The rapper got the crowd excited as she joined Christina for the hit song

The Liberation Tour is Christina's fifth concert tour and first in a decade.

The concert also drew Huma Abedin, 42, who was vice chair of Hillary Clinton's 2016 presidential campaign.

Huma wore a black sweater with 'November is coming' written in white across the front in reference to the upcoming mid-term elections.

Date night: Hillary and Bill smiled as they arrived at Radio City Music Hall for the concert

Holding on: Bill wrapped an arm around Hillary as they made their way into the concert

Later on: She was spotted later heading out in a purple ensemble

Coming soon: Huma Abedin wore a black sweater reading 'November Is Coming' on the front