The American Idol judge, 44, enjoyed a "very flirty" night out with Chmerkovskiy, 34, after he attended her concert at Foxwoods Resort Casino in Connecticut on Saturday, Us Weeklyreported.
The couple, who were part of a larger group, reportedly danced at Shrine Nightclub and talked the night away. Chmerkovskiy allegedly stayed at Lopez's side even when she was the only one of the two hitting the dance floor.
"Maks was whispering into her ear and hugging her," an eyewitness told Us. "They looked very flirty with each other... She had a huge smile on her face and looked like she was having a great time."
At the end of the night, the pair reportedly held hands and hugged goodbye. However, they went their separate ways, as Chmerkovskiy left with a guy friend and Lopez remained with the group.
Lopez recently dumped backup dancer-turned-choreographer Casper Smart, 27, in an "amicable process that started a few months ago," according to an Us insider.
Rumors have since been circulating Lopez may be dating Chmerkovskiy. Sources have claimed they kept in touch after Chmerkovskiy performed with her at the American Music Awards last November. The couple reportedly met through Lopez's best friend Leah Remini, who had competed on Season 17 of Dancing with the Stars and hopes the two performers will date.
However, the "I Luh Ya Papi" singer rejected dating rumors on Twitter via two different tweets earlier this month.
"No I'm not. #rumors #nottrue," Lopez wrote, further clarifying things in her second post.
"No I'm not. (dating anyone new already.)," she tweeted.
Chmerkovskiy has apparently been single since his last relationship with Sports Illustrated supermodel Kate Uptonended in December although reports have circulated for weeks he's seeing Meryl Davis. Chmerkovskiy and Davis, who won Season 18 of Dancing with the Stars together, have both repeatedly insisted there's nothing romantic going on between them.
It has yet to be confirmed whether Lopez and Chmerkovskiy will return to their respective reality shows. Chmerkovskiy has recently suggested he might like to serve as a Dancing with the Stars judge going forward, while Lopez is expected to sit on Idol's judging panel again with Harry Connick Jr. and Keith Urban for Season 14.