In the clip, Lopez goes completely makeup-free with her hair styled in a messy bun as she reenacts the "White Girl Anthem" lyrics on Dubsmash with a shirtless Smart.
"#dubsmash #starbucks #chipotle #yogapants #morestarbucks #yasssss," Casper captioned the video.
It's definitely refreshing to see the 46-year-old dressed down, without her hair and makeup done -- doesn't she look so different?!
It's also pretty clear that the on-again-off-again couple has rekindled their romance. Lopez and Smart were spotted packing on the PDA while celebrating New Year's Eve in Miami last month and the "Shades of Blue" star sort of confirmed their relationship while chatting with Ellen DeGeneres.
Though Jen says they have no plans to tie the knot anytime soon, she is open to getting married again.
"I love getting married," she said during an interview with the "Today" show last month. "I really want to get married in a church, with a big dress."
What do you think about J.Lo and Casper's funny Instagram video? Sound off below and check out the gallery above to see more stars without makeup!