The actress, who appeared in the famous Australian soap from 1988 to 2013, broke the happy news on her official Facebook account today (1 March).
Alongside a framed photograph of herself and her husband Stuart Webb, Kate wrote a message to her fans telling them she was pregnant and explaining why she hadn't confirmed rumours sooner.
The 35-year-old wrote: "IT IS WITH GREAT EXCITEMENT that Stuart and I announce we are expecting our first child.
"We can assure you any secrecy up to this moment has been nothing more than us protecting what is most sacred - a new life that was far from reaching its 12 week milestone."
After rumours began to circulate as early as January, Kate went on to explain: "Thank you to all who have respected our privacy over these past weeks allowing us the privilege every couple deserves - to share the wonderful news ourselves.
"It really is such a special time for us and we couldn't be happier! KR x"
Kate married her husband, a former NRL player and current league coach, in 2010 in Tasmania.
The couple started dating in 2008 and kept their wedding a very private event.
The actress now presents on Nova 96.9 radio station in her native Australia after leaving her Home And Away character Sally Fletcher behind her.
She returned to the soap last year for an eight-week stint to coincide with the show's 25th anniversary. An emotional storyline saw Sally battle to save daughter Pippa, who was suffering from a terminal illness.
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