Stamos and McHugh have been together for two years and became engaged on October 22 in Disneyland.
"I asked...she said yes! ...And we lived happily ever after💍," Stamos captioned his Instagram post.
In December, just two months after their engagement, the couple announced that they were expecting a child together.
"I always wanted to be a dad. Clearly I had to do some work on myself first," the Full House alum told People in December.
"I think I'm going to be a fun dad, I've been practicing for a long time," Stamos said.
He added, "I've done every schtick thing you could do with a baby on TV, every slow Elvis song, every joke and bit and diaper gag - I'll probably just do all that stuff."
The couple was set to be married on Saturday, but on Friday they were facing an unexpected complication.