The powerhouse singer, 37, surprised the sold-out crowd at Radio City Music Hall with a very special guest: rapper Lil’ Kim.
Both musicians have a history together, having collaborated back in 2001 on the Moulin Rouge soundtrack hit “Lady Marmalade” (alongside Mya and Pink) and again in 2002 on Aguilera’s Stripped track “Can’t Hold Us Down.” The LaBelle cover won them the Grammy for best pop collaboration with vocals.
Aguilera was in the midst of singing the song when she brought Lil’ Kim out, telling the crowd on Wednesday, “We got a surprise — Lil’ Kim, Lil’ Kim, Lil’ Kim!”
The rapper, 44, then appeared on stage decked out in a sparkling grey bodysuit with sheer panels, spitting her iconic “Lady Marmalade” rhymes once again.
Among the folks watching from the audience was former President Bill Clinton and Hillary Clinton, who got cheers of their own when they arrived at the famed venue. Later, they posed with Aguilera backstage. Bill, 72, and Hillary, 70, wore classic pants and blazers as Aguilera rocked a corseted red ruffle gown.
That gown is one of the many looks Aguilera wears during her Liberation Tour.
Other looks — from designers like Milligan Beaumont, Gareth Pugh and Joshua Kim — include a high-shouldered sequin gown, an oversized jacket, and a black and red leather ensemble with chaps, straight from her “Dirrty” video.
There’s also a dramatic wedding-inspired white tulle gown that she wears while singing the ballad “Unless It’s with You.” Afterwards, Aguilera helped facilitate a marriage proposal onstage. She started a similar tradition late last month when her tour kicked off at the Hard Rock Live in Hollywood, Florida.
This is Aguilera’s first tour in a decade. Her setlist includes many songs from her new album Liberation, including “Fall in Line,” “Maria” and “Accelerate” — as well as old favorites like “Fighter,” “Beautiful,” “Ain’t No Other Man,” “Genie in a Bottle,” “Can’t Hold Us Down,” “What a Girl Wants” and “Come on Over (All I Want Is You).”
“What an amazing warm welcome back to the stage after 10 years (too many!),” Aguilera wrote on Instagram after her first show, captioning a gallery of photos from the tour. “[It] felt like coming HOME again!!”
“Thanks to all of you in Florida for your beautiful energy,” she added. “I feel fulfilled and alive and cannot wait to see you Fighters in New Jersey on Friday. #LiberationTour.”
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Liberation was Aguilera’s first new studio album since 2012’s Lotus.
Though she hasn’t put out a full LP since then, there have been singles. In 2013, she guested on Pitbull’s “Feel This Moment,” Mexican singer Alejandro Fernández’s cover of “Hoy Tengo Ganas de Ti,” and A Great Big World‘s “Say Something.” That same year, she recorded “We Remain” for The Hunger Games: Catching Fire soundtrack.
She appeared on a remixed version of Lady Gaga‘s 2014 single “Do What U Want.”
In June 2016, Aguilera released “Change” — a song dedicated to the late Christina Grimmie and the victims of the Orlando nightclub shooting. Two months later, she dropped a disco song called “Telepathy” for the soundtrack of Netflix’s The Get Down.
Of course, in her time away from music, Aguilera has remained busy in her personal life. In 2014, she got engaged to fiancé Matthew Rutler. The couple are parents to 4-year-old daughter Summer Rain. Aguilera also has a 10-year-old son Max Liron from her first marriage to ex Jordan Bratman.
Aguilera told PEOPLE this summer that along with her dancers, Summer will be joining her on tour.
“She’s a mama’s girl and I’ll definitely be taking her on the road with me,” the Mickey Mouse Club alum said of her only daughter. “She’s going to learn to see life through a different set of eyes.”