"Merry Christmas from us," the shoe designer captioned the picture.
The pair have been together shortly after Karl split from his wife of 21 years, Cassandra Thorburn.
The 43-year-old discussed finding love so soon with Stellar Magazine.
“I certainly did not expect to meet someone five months after I broke up with my wife,” Stefanovic said.
“That was not planned. I did not know her before. I met her on a boat in Sydney. We have a really lovely relationship, but it’s got to be slow for a variety of reasons. I’m not going to share too much on that publicly because I don’t think that’s fair on anyone involved.
“It was unexpected and lovely, but we’re going to try to keep a level of privacy to how we’re going and what we’re planning, especially considering I have three beautiful children who need to be taken into consideration.”
This article originally appeared on New Idea.