The Guru star met his fiancee when they were paired together on U.K. reality TV show Strictly Come Dancing in 2010, but they didn't start dating until the following year (11).
Cacace, who won the most recent series with Olympian Louis Smith last month (Dec12), took to her Twitter.com page to tell fans the good news.
She writes, "Sorry I have been a bit quiet, wanted to wish you all a very happy new year. I’ve had a wonderful time and have some amazing news... All I need to say is Jimi Mistry has made me the happiest girl in the world.... Engaged."
Her actor fiance followed with his own tweet, "You’ve made me the happiness (sic) man... Thank God she said yes."
Mistry was previously married to long-term partner Meg Leonard but they divorced in 2010 after 17 years together and have an 11-year-old daughter, Elin.
Cacace parted ways with her former fiance and fellow Strictly Come Dancing star Vincent Simone in 2007 and later embarked on a three-year romance with ex-EastEnders actor Matt Di Angelo, another of her TV dance partners, but they split in 2010.