The Girls actress flashed her diamond sparkler for the first time at Sunday's Vanity Fair Oscar party. Williams, 25, looked pretty in pink wearing an Emilia Wickstead dress that featured an open back.
Williams and Van Veen began dating three years ago after meeting through mutual friends. And she's not the only Girls star who's in love: Lena Dunham is dating fun. Guitarist Jack Antonoff, while Zosia Mamet is with actor Evan Jonigkeit. Jemima Kirke, meanwhile, is married to lawyer Michael Mosberg.
Other famous faces who showed up for Vanity Fair's annual bash included Lupita Nyong'o, Elton John, Reese Witherspoon, John Travolta, Selena Gomez, Samuel L. Jackson, Mindy Kaling, Judd Apatow, Rosie Huntington-Whiteley, Tim Tebow, Sofía Vergara, Andy Samberg, Sheryl Crow and Ed Sheeran.