Ojani Noa – the star's first spouse - had planned to wait in line and serenade his former wife with one of her own songs when auditions opened in California on Wednesday (22.09.10).
However, J.Lo – who was unveiled as a new member of the judging panel this week along with Aerosmith frontman Steven Tyler – told the show's producers, Fox, she would be uncomfortable with Cuban-born Ojani appearing leading to him being told by bosses he could be arrested if he went ahead with his plans.
A friend of Ojani told RadarOnline.com: "Jennifer got Fox to make sure the screeners would not let Ojani anywhere near the auditions.
"Fox made it clear that he was not welcome and that he could be arrested if he showed up, so he backed-out at the last minute.
"It was a shame because all he wanted to do was to showcase his voice and show people that he can really sing too."
Ojani, 36, married Jennifer in 1997 after meeting her while working as a waiter. Their marriage lasted less than a year and they initially parted on good terms, but the pair have fallen out in recent years, after Jennifer hired and subsequently fired Ojani as head chef of her now closed Latin restaurant Madre's in 2002.
He has since been banned from publishing a tell-all book he wrote about the 41-year-old star by one court, and last year a judge ruled he was also not allowed to commercially release footage from the couple's honeymoon.
The source added: "Whenever Ojani tries to do something Jennifer just tries to block it any way that she can – nobody really knows what she's so paranoid about."
Since divorcing Ojani, Jennifer dated rapper P. Diddy, married and divorced dancer Cris Judd, got engaged to actor Ben Affleck and finally settled down and married singer Marc Anthony, with whom she has two-year-old twins Max and Emme.