For her opening monologue, the singer gave a performance of Santa Claus Is Coming To Town while dressed in a tuxedo, before inviting the Radio City Rockettes to join her on stage.
During the final notes of the song, Lopez stripped off the tux to reveal her outfit underneath - the now-famous green dress she first wore in 2000.
“Now it’s really Christmas,” the 50-year-old said to cheers from the crowd.
Earlier during her monologue, the third-time SNL host opened up about all that she is grateful for as the year comes to an end, including the opportunity to wear the jungle-print Versace dress on the runway during Milan Fashion Week and her March engagement to Alex Rodriguez.
— Saturday Night Live - SNL (@nbcsnl)December 8, 2019
“I have been so blessed,” she said. “First off, I got what every girl from the Bronx dreams of: getting proposed to by a Yankee.
“I had the biggest movie opening I’ve ever had, that included a lap dance from Cardi B. I went on a sold-out tour. And I slayed the Met Gala.”
After adding that she will also be performing at the Super Bowl half-time show, the Hustlers star then recalled: “I walked the runway in Milan, for the first time, wearing a dress I wore 20 years ago”
“You know some people said I looked better now than I did then,” she said. “And I’m not bragging, that’s just, you know, gossip.”
Lopez last appeared on SNL in 2010, as host and musical guest.