J Lo was honored with the Michael Jackson Video Vanguard Award at the show -- one of the biggest moments of the night.
Lopez performed a medley of hits including "Ain't It Funny" and "I'm Real" with Ja Rule -- while A-Rod watched gleefully from the crowd.
In fact, there was a hilarious gif of Alex's face lighting up as he watched J Lo twerk her ass off during the performance.
After the show, the couple hit up Beauty and Essex in New York City -- where they continued to dance the night away together while the DJ played some of Jen's hits ... along with other hip-hop classics.
Lopez even rapped along to a Cardi B song while the crowd cheered her on.
Jenny arrived to the show with her two kids -- but put them to bed before she hit the after-party.
Hey, mama's gotta let loose!