Mary-Kate and Ashley Olsen  took a break from their own busy fashion week to celebrate another big brand, Estée Lauder, for the launch of new fragrance Modern Muse at the Guggenheim Museum last night in NYC. The sisters posed for pictures with makeup artist Tom Pecheux as they mingled at the event, which also brought out a host of models, designers, and famous faces, including Drew Barrymore , who chatted up an Emilio Pucci-clad Julianne Hough, and Maggie Gyllenhaal  and Peter Sarsgaard , who shared a sweet moment on their way into the party. The beauty bash was also attended by Michelle Dockery, Hailee Steinfeld, Linda Evangelista, Iman, and Hilary Rhoda. We were on the red carpet to chat with the evening's guests like Drew, who shared details of how being a mom has changed her beauty routine, as well as Julianne, who shared with us her own muse — Watch POPSUGAR Live!  for our interviews with Drew, Julianne, and more!
While Mary-Kate and Ashley made headlines for the debut of their new designs for their lines — The Row and Elizabeth and James  — during this year's New York Fashion Week, the latter sister also made news for more personal reasons. Earlier this week, it was reported that Ashley is dating David Schulte , the CEO of luxury eyewear brand, Oliver Peoples .
Drew Barrymore  hit the red carpet for Estée Lauder's Modern Muse party.
Mary-Kate and Ashley Olsen  posed with makeup artist Tom Pecheux.
Emilio Pucci-clad Julianne Hough and Drew Barrymore  linked up at the Modern Muse event held by Estée Lauder.
Maggie Gyllenhaal  shared a sweet moment with her husband, Peter Sarsgaard , at the Guggenheim Museum.
Michelle Dockery attended Estée Lauder's Modern Muse event in NYC.
Hailee Steinfeld stepped out for the Estée Lauder fragrance launch.
Julianne Hough and Drew Barrymore  had a laugh.
Joan Smalls wore a purple silk dress.
Hilary Rhoda was in attendance at Estée Lauder's party in NYC.
Linda Evangelista wore a black gown.
Peter Sarsgaard  dressed up in a suit.
Carine Roitfeld linked up with designer Olivier Theyskens.
Iman wore a maroon number to the Estée Lauder party.