Hilty, 32, wore a Badgley Mischka dress to the Saturday night ceremony, while Gallagher, 33, wore a J Lindeberg suit, People reported.
The couple met at a fitness class when they were both working on Broadway.
"We were so excited to be married that we skipped the engagement altogether!" said Hilty.
Hilty, a former "Smash" cast member who currently stars on NBC's "Sean Saves The World," and Gallagher, an actor and musician, are set to perform together at WitZend and the Catalina Jazz Club in Los Angeles Nov. 21 and 22.