The 43-year-old, who has been divorced thrice, recently celebrated her one year anniversary with her 25-year-old dancer boyfriend recently.
Lopez had trouble when her former husband Ojani Noa tried to sell their sex tape after divorce. She is said to be taking no chances this time and has asked Smart to sign a non-disclosure agreement, reported Radar Online.
"Casper signed a non-disclosure/confidentiality agreement when he began working for Jennifer lopez, as she requires all of her employees to do. Jen has been around long enough to know that anyone she dates could possibly turn on her and choose to go to the press if the relationship sours," a source said.
Smart was only too happy to sign the legal document - which will prevent him for ever discussing their professional and private relationship if they split.
"Casper had absolutely no qualms about signing the agreement, and has told Jen on multiple occasions that even if he didn't work for her, he would have signed the contract. Jen loves him even more for that," she added.