The Boyzone singer shared his happy news via Twitter, saying that he popped the question to his girlfriend TWICE and she accepted both times!
"It was the happiest day of my life," he said.
This will be Ronan's second marriage. He was previously wed to Irish model Yvonne Keating, the mother of his three children: Jack, Marie and Ali. He split with Yvonne in 2010 following his affair with a Boyzone backing dancer.
Ronan later said he never thought he'd find happiness again - until he met Australian Storm.
"Storm came into my life when I was lost and I was struggling," he told Daily Mail. "I was in a very dark place and very lonely. I found Storm and she found me when we were both going through difficult times (Storm had recently divorced), and it's been incredible. We're very lucky to have each other."
They met via the Australian version of X Factor, where Ronan worked as a judge and Storm was on the production team.
Last year, Ronan said: "I love her and I want to be with her for the rest of my days. She makes me happier than I've ever been."