The rep added to E! News: "It looks like she was happy to have it happen, but it was not consensual."
Along with bidding on a prize, Lapo, 38, also donated his Ferrari 458 Camouflage in order to raise money for AIDS research.
He posted a picture of the car on Instagram and wrote: "I have driven every road with this one and only, unique and beloved Ferrari 458 Camouflage I conceived and customized for myself."
"Tonight I am donating this car to @amfAR and I hope someone as passionate as me will bid very high to become the new owner of this jewel and together raise money to defeat Aids."
Meanwhile, other stars who attended the gala included Katy Perry, Orlando Bloom, Dame Helen Mirren, Kirsten Dunst, Faye Dunaway, Elle Fanning, Karlie Kloss, Rosie Huntington-Whiteley, Karolina Kurkova, Bella Hadid, Alessandra Ambrosio, Jourdan Dunn, Adriana Lima and Heidi Klum.
Leonardo DiCaprio gave a speech and auctioned off a week-long stay for 12 people at his Palm Springs home for $500,000 (NZD$739,000).