She said their parents just met each other recently (it had been tough to meet earlier since Fisher's parents are in Canada and Underwood's folks are in Oklahoma).
On Saturday, Fisher, 29, joined Underwood at a pre-Grammy dinner saluting industry icons in Beverly Hills, where she performed "Cowboy Cassanova."
As she performed, "Mike kind of bobbed his head along," says a partygoer. "Mike definitely was smiling proudly at his fiancee while she was singing. Her performance was flawless and got a standing ovation. She was great."
The two - who got engaged in December - made their first public appearance together earlier this month at the annual Bell Sens Soiree, a fundraiser for the Sens Foundation, the charity of his hockey team, the Ottawa Senators.