The property tycoon has asked the Strictly contestant to be his wife, and an overjoyed Holly has accepted.
Thirty-eight-year-old Nick went down on one knee on a beach in the Maldives with the words "Will you marry me" spelled out in flames.
Holly posted a picture of the romantic scene on Twitter with the accompanying caption: "And I said YES!!! ♥ Happiest day of my life!!!!! Xxxx."
Nick whisked the 28-year-old Australian away to the Indian Ocean island on Wednesday for a Christmas break to help her unwind after the Strictly Come Dancing final.
The actress and model has been dating Nick since 2009 after meeting him at a mutual friend's dinner party.
She has said of their meeting: "I didn’t know anything about him. I just thought 'Cor, if I didn’t fancy you so much, we’d be the best of friends. Instead, I just want to make out with you all the time'."
Lucky Holly freely admits that her loved-up joy sometimes rubs friends up the wrong way.
"I've got such a disgusting, wide, smug grin on my face all the time that my friends just want to slap me. I’ve never been so happy...
"I am a spoilt brat. My friends and my sister say: 'I hate you!' when I show them what he's bought me."
Nick has worked hard to establish a £9 billion property portfolio. Along with his brother Christian, the shrewd businessman build up their business Candy and Candy, which they founded with a £6,000 loan given to them by their grandmother.
He owns homes in Monaco and London – where he resides with Holly - and has a private plane and a £50 million luxury yacht.