Reports said Simpson threatened to attack Lohan after she and her sister, Jessica, were denied admittance to Lohan's party after the MTV Movie Awards Saturday night.
The Simpson sisters went to comic Jimmy Fallon's party instead and there was reportedly a confrontation between Ashlee and Lindsay when the "Love Bug" star showed up later, the World Entertainment News Network reported Wednesday.
However, a Simpson representative told WENN Ashley never threatened Lindsay and everyone "had a great time at Jimmy's party."
And a Lohan rep told the New York Post's Page Six that Simpson sisters' names were "misplaced on the list," which is why they were denied entry to the party.
Celebrity Breakups and divorces of 2014 [PHOTOS]