The "Saturday Night Live" star, 41, is nominated for best actor in a television series, musical or comedy for his role in "Barry," while his date -- the 38-year-old "O.C." alum -- was there for moral support.
The new couple's first public outing comes less than a month after being spotted grabbing coffee together in his hometown of Tulsa, Oklahoma. According to TMZ, the Starbucks date included hand-holding and some of Hader's family members.
Bill and Rachel previously co-starred in the 2013 romantic comedy, "The To Do List," which was written and directed by Maggie Carey, Bill's then-wife. They split in 2017 after 11 years of marriage and share three daughters: Hayley Clementine, 5, Harper, 7, and Hannah Kathryn, 10.
Meanwhile, Bilson split from "Star Wars" actor Hayden Christensen in 2017 after nearly a decade together. They share a 5-year-old daughter named Briar Rose.
The 77th Annual Golden Globe Awards ceremony aired live on NBC from Los Angeles on Sunday, Jan. 5.