The post was soon inundated with birthday wishes, including from fellow actor Jane Hall who wrote: "Happy Birthday RUCHUD!!!!!!! We all love you so very much. You are a wonder XXXX."
Sara Wiseman also shared the love, commenting: "❤️❤️❤️❤️❤️❤️."
The milestone comes just three weeks after Rebecca and Richard marked their 20 year wedding anniversary.
The Back To The Rafters actress celebrated the feat by taking a trip down memory lane on her Instagram, sharing photos from special moments over the years.
"20 years ago today this happened," the actress wrote.
"What a magical wonderful day it was. I am the luckiest because you big R are all the things. Happy Anniversary my love ♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️♥️."
Rebecca and Richard originally met on the set of Aussie TV movie Dogwoman in 1999 - but their story goes back much further than that.
"In walks this beautiful, tall New Zealander who happened to live on the same street as me when I was five," the Back To The Rafters actress told Woman's Day last month about her and Richard's first meeting.
Two years later, the couple tied the knot on a beach in Thailand before welcoming their son, Zachary, three years after that.
"I can't imagine growing old with anyone else," Rebecca told the publication.
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