Sources close to the pair confirmed Mark went down on one knee during a romantic holiday in Dubai, the exotic location where they got together nine months ago, and Michelle excitedly tweeted the news.
"THANK YOU for all the lovely messages, and yes it's true @markwright_ and I are engaged!! We are so SO happy :-) xxx," wrote the bride-to-be.
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The couple – both 26 – are said to be "blissfully happy" after Mark's proposal, which took Michelle completely by surprise.
He asked the all important question on a beach, presenting his girlfriend with a sparking ring – which he has designed himself and has been describing to friends as a "monster rock" – thought to be a five-carat diamond.
The lovebirds are back from holiday and Mark updated his Twitter followers, saying that he had "just woken up in the UK after an amazing holiday" – in a post that was retweeted by Michelle.
Mark and Michelle's love story began in Dubai, after they fell for each other at a New Year's Eve party.
"We are really happy," Michelle said in June. "I'd met Mark before, but a group of us met up, and it was an amazing night. We went to a festival on the beach and to a club and stayed up all night. Was it a night that changed my life? Perhaps."
Since then, she has proven a hit with Mark's family, including his sister Jess. "I absolutely love her," the TOWIE star told the Daily Star in August. "She fits in with the family really well. She's very down to earth. What you see is what you get."
Both have been engaged in the past. Michelle was due to wed Max George of The Wanted but called off the engagement in July 2012. Meanwhile Mark cancelled his plans to marry his former TOWIE girlfriend Lauren Goodger in August 2011.