Alessandra Ambrosio turned heads on Wednesday at the 2014 ACRIA Holiday Dinner. The 33-year-old model stunned in a long black gown by Alexandre Vauthier. The dress bared the entirety of her right leg, and featured an open panel revealing a good portion of her back. Ambrosio paired the outfit with black patent Christian Louboutin pumps. The 19th annual ACRIA Holiday Dinner honored playwright and activist Larry Kramer and photographer Bruce Weber. The event seeks to raise funds for HIV\/AIDS research, and benefit and provide services for those affected by the disease. Ambrosio has walked the runway for such brands as Prada, Chanel and Oscar de la Renta. She is best known as a Victoria's Secret Angel, and modeled a $2 million 2014 Fantasy Bra at the company's annual Victoria's Secret Fashion Show this week.