The pair shared a meal at trendy New York City eatery Per Se on Saturday night, a restaurant employee told Us Weekly.
Another eyewitness revealed that Lopez and Cooper spent much of the evening together at the restaurant, which is located in Columbus Circle.
Representatives for Lopez and Cooper have not commented on the report.
Lopez filed for divorce from husband Marc Anthony in July, with the American Idol judge later suggesting that Anthony didn't treat her properly.
Cooper and former girlfriend Renée Zellweger reportedly ended their two-year romance in March.
> Marc Anthony denies Jada Pinkett Smith affair rumours
> Marc Anthony, Jennifer Lopez 'still close friends'
Watch Bradley Cooper in the Hangover Part II trailer below: