The singer nearly toppled over in her high heels after shimmying to the first song, busting out some of her infamous choreo.
Fallon first told Lopez that since she is the "pioneer" of dance breaks in her music videos, their interview would be full of them. Basically, anytime an air horn sounded during their chat, they had to simply get up and boogie down.
The late-night host first asked Lopez what her favorite music video of all-time was, as she will receive the MTV Video Vanguard Award at the VMAs on Sunday.
"Janet Jackson. 'Pleasure Principle,'" Lopez replied. "Of all time, yes. It's probably the reason I decided like I want to be a singer, I want to be a dancer. I can do this."
That's when the buzzer went off and Lopez and Fallon got up to dance to a instrumental version of the singer's 2018 hit "Dinero." When she realized what song it was, the "World of Dance" judge brought out her choreography.
As in the interview continued, Lopez teased her upcoming VMA performance.
"I have to just be me," she said. "I have to just do what I do. We're going to try to bring the thunder."
As the dance breaks continued, Lopez brought out her moves to her chart toppers "Waiting for Tonight," "El Anillo," and "Let's Get Loud."
Lopez, who is in the midst of her Las Vegas residency, joked that she didn't even know her own songs, as she did her "On The Floor" choreography at first when they played the tune to "El Anillo."
"That was a fail," Lopez explained. "Because I thought you were playing 'On The Floor' and you were playing 'El Anilio.' I can't recognize my own songs!" The interview ended with Lopez and Fallon whipping their hair and dancing in front of fans. Watch the full clip above.
Also during her appearance on the late-night show, the Grammy winner spoke about her upcoming romantic comedy "Second Act" starring Ventimiglia.
The "This Is Us" star was on the show earlier this week and spoke about how Lopez "specifically requested" him for the role. Lopez said that watching Ventmiglia "play a dad" on the NBC drama made her know that she wanted the "heartthrob" for the film.
"We were developing the script, there was only one person I ever saw," she said. "I was just like this has to be Milo. This has to be the guy from 'This Is Us.'"
"The Wedding Planner" star expressed that she's excited to bring the romantic comedy back, especially now.
"You need that funny, quirky look at life," Lopez said. "That romantic look at life. I think things are tough sometimes and we need that escape."
Speaking of romance, Fallon also asked the "Shades of Blue" star about her boyfriend Alex Rodriguez and their shared love of having Lopez dance on tables.
Fallon brought up how she and the MLB legend recently went on a vacation to Italy, where the a restaurant played "Let's Get Loud" and Lopez got up on a table and sang.
"I have always been the girl who dances on tables," she said. "Even before I was famous."
The MTV Video Music Awards air this Sunday at 9 p.m. EST on MTV.