The boys of 5SOS will join Mikey at the altar, as he asked Luke Hemmings and Ashton Irwin to be his groomsmen, and Calum Hood to be his best man.
Michael revealed the exciting news to Fitzy & Wippa from Nova, as they are broadcasting their show live from LA all this week, where the boys now reside.
"This is actually the first time I've said this but I've asked all these guys to be my groomsmen," Michael revealed on the red carpet at the G'Day USA gala in Los Angeles on Saturday.
Luke Hemmings added: "The clock was running out. We were a bit worried. 'When is he gonna ask us?'"
Michael explained why he chose Calum to be his best man over the other boys: "We were talking about it for a long time and the only reason I picked Calum is I've known him the longest".
At the time of the proposal, Michael posted a series of beautiful sunset shots where he proposed to long-term girlfriend, and they're honestly breathtaking.
"I was lucky enough to ask the love of my life to marry me in the place it all began for us," Michael wrote.
"In the last 3 years she has helped evolve and shape who I am in ways I could never have imagined. I couldn’t ask for anyone better to spend the rest of my life with. I love loving you, Crystal. ❤️"
Michael and Crystal started dating in 2016, and have been inseparable since.