(Cover) - EN Showbiz - Jennifer Lopez has slammed claims she is set to walk down the aisle after a comment about her wedding dress appeared online.

A posting on fashion designer Roberto Cavalli's Twitter page claimed he is working on a wedding gown for Jennifer, who has been beset with rumours she is tying the knot with her 24-year-old beau Casper Smart.

The comments appeared on Roberto's profile on Monday and have since been deleted.

"Today , Jenifer Lopez. Call me...... She ask me. To create a special dress. For her next weding. !" he appeared to tweet. "Wich color ... Do you advise me. (sic)?"

However Roberto's representatives told People his account has been hacked into and there is no truth to the claims. The designer's representative said the comments are "completely false".

Jennifer's representatives have also denied reports of a marriage.

The actress-and-singer and backing dancer have been dating since her split from her third husband Marc Anthony.

They were spotted in Acapulco, Mexico, this week, where Jennifer is filming a music promo. Casper has also been by his girlfriend's side for tapings of American Idol, on which she is a judge.

"Jennifer thinks she is very lucky to have met Casper," a source said. "There is a lot of love between [them]. He treats her like a queen."

Casper is also thought to have formed a close relationship with Jennifer's four-year-old twins Max and Emme.

As the relationship gets reportedly serious, Jennifer's manager Benny Medina has said he wishes the actress would slow down and be more careful about her choice in men.

"The thing that I always sort of wished is that she would give herself time to just naturally meet someone, instead of having obsessive guys pursue her," he told the April issue of Vogue.

"And she never half does anything. When she commits to anything in her work, her life, or her relationships, she is in it." (C) Cover Media