WTAE-TV reports Robertson told the couple to always love and forgive one another as they were wed Saturday morning at a Field & Stream store near Pittsburgh.
Robertson popped in for the nuptials of Mehgan Cook, who sported a camouflage sash on her dress, and Charlie Miller, who was completely clad in camo gear.
The two hadn't planned on marrying at the store but Cook said they were eager to meet Robertson.
"I was going to cancel the wedding 'cause I heard Willie was coming," Cook told KDKA-TV.
Instead, Cook said, her mother came up with the idea of a wedding at the store and they got a surprise when Robertson appeared during the ceremony.
"That's a first for me, it's good to be a part of that," Robertson said. "They look like my kind of folks with the camouflage . that was cool."
On the "Duck Dynasty" Season 4 premiere, which aired Wednesday, family members threw a surprise wedding for patriarch Phil Robertson, wearing a black jacket over camouflage garb, and his wife, Miss Kay. They could only afford a justice of the peace when they married 48 years ago.
The show drew 11.8 million viewers on the A&E channel, making it the No. 1 non-fiction series telecast in U.S. cable television history in total viewers as well as all key demographic groups.
Cook said she had been engaged to another man, but he died in a car crash four years ago. But she met Miller at the scene and eventually the two started dating.
"I never thought it would happen again," Cook said, tearing up.