The on-again couple are holidaying in Hawaii amidst claims they are set to get engaged soon.
As the pair enjoyed a pre-Christmas break in Hawaii, the singer posted a snap of the pair under a rainbow while standing in front of a waterfall.
To which the 41-year-old Brit actor replied: "Gold."
The couple escaped to the tropical islands with the actor's seven-year-old son Flynn for a beach break, before spending the festive period in Katy's home state of California.
Their family holiday comes as the pair have been surrounded by engagement rumours in recent weeks.
A source close to the couple told respected magazine People: "They are doing incredibly well. They seem beyond happy and very serious.
"Katy is amazing with Orlando’s son. She is very involved in his life. It makes Orlando very happy. They will spend part of the holidays together and some days apart as well. They have a trip planned to celebrate New Years’ together."