Scarlett Johansson and Donatella Versace were the women of honor at amfAR’s star-studded New York gala on Wednesday night, held in the gorgeous ballroom at Cipriani Wall Street.

The event kicked off New York’s fashion week with heartfelt speeches, emotional and energetic performances and an auction with items including Andy Warhol uniques and a Moet & Chandon champagne vending machine. AmfAR, one of the world’s leading nonprofit organizations dedicated to support AIDS research, HIV prevention and treatment education, is dedicated to “making AIDS history,” as amFAR chairman Kenneth Cole announced from the podium.

Wednesday’s gala was supposed to be hosted by Lena Dunham, but instead Iman appeared onstage to announce that she would take over hosting duties since Dunham felt “under the weather.” Later, “Girls” star Zosia Mamet would assure the audience that the chance to wear a gown and be in a room of successful and handsome gay men is Dunham’s fantasy: “She’s not faking, you guys,” Mamet joked.

But the evening’s main event came when Mark Ruffalo presented an award to Johansson, his friend and “Avengers” co-star.

“Scarlett is no armchair humanitarian,” Ruffalo said. “She’s the real deal.”

He praised the actress for her dedication to philanthropic work. “It’s probably no surprise to you that we live in turbulent times,” he added. “But if there are any young men or women out there that are looking for a role model, they need look no further than Scarlett Johansson.”

Johansson took the stage and praised Ruffalo with equal sincerity. “Thank you Mark, for not just playing a super hero, but embodying the spirit of one in your everyday life,” she said.

The actress then told a story about her mom’s best friend who died of AIDS in 1993. She talked about their romance. “His compliments and presence in her mom’s life,” Johansson said, were able to fulfill so much of what her mom was missing at the time. “So, perhaps it was even more romantic than any conventional ideal,” Johansson said, dedicating her award to the millions of people who are still suffering from AIDS and those who are working to end it.

Naomi Campbell did the honors of introducing Versace who gave a rousing speech as well. The evening’s other guests included Alan Cumming, amfAR CEO Kevin Robert Frost, Chloe Sevigny, Diane Kruger (who appeared onstage briefly during the auction to give an awkward pitch for bidding on tickets to the Golden Globes), Heidi Klum, Janet Mock, Jeremy Piven (who referred to himself as the “poor man’s Tom Ford”), Zoe Kravitz and Paris Hilton who put on a show of her own in a flowing gold gown. Dozens of models also attended, dressed to the nines, including Adriana Lima and Alessandra Ambrosio.

Guests were served burrata with grape tomatoes and basil, strip steak with string beans and tri-color carrots, plus mini pastries for dessert. Ellie Goulding rounded out the fundraiser with a three-song set of her hits — “On My Mind,” “Burn” and “Love Me Like You Do” — that brought the whole ballroom to its feet.