Johansson, 32, and Jost, a 35-year-old co-anchor of the show's Weekend Update, first sparked romance rumors this past spring and E! News confirmed in June they are dating. A source told E! News exclusively on Sunday that the two are "going strong."
The SNL party took place at the Tao Uptown restaurant in New York City right after the season 43 premiere and weeks after Johansson finalized her divorce from Romain Dauriac, with whom she shares a 3-year-old daughter, after two years of marriage. Sunday would have marked their three-anniversary.
At the bash, Johansson wore a black-trimmed white crop top and black pants. Jost sported a black T-shirt and dark blue jeans.