Marc by Marc Jacobs

Stefanie Keenan/Sipa Press

Stefani was effortlessly chic in a little black Marc by Marc Jacobs dress complete with asymmetrical zipper detailing at the Domino: The Book of Decorating launch party in Beverly Hills. The trendy mom gave a pop of color to the inky look—which included a L.A.M.B. clutch and heels—with her signature red lips.