"Never thought I'd say this, congratulations to my ex husband on his engagement to my ex designer," Michelle tweeted. "No bitterness, no regrets, happiest ever."
Michelle and Michael's 20 year marriage came to an end in 2011, when Michelle accused her spouse of being unfaithful with Samantha. Michael has always insisted that his relationship with Michelle was over before he started seeing Samantha.
Mum-of-three Michelle has previously revealed she cried herself to sleep every night immediately following the split.
Talking to Jane Garvey on Radio 4's Woman's Hour, Michelle confessed, "I cried myself to sleep every night and during the day as well. I was just absolutely distraught.
"I thought, 'How could you, with a member of my team that I've managed for four years? How could she lie to me so much and stay in my house next door and have dinner at night with my kids? How could he have a relationship with her?' I was absolutely shattered by it."
Now it seems Michelle is in a much more positive place, with a new passion for health and fitness.
Just recently, the 43-year-old showed off her toned stomach in a post-workout selfie shared with her 833,000 fans on Twitter.
Smashed it!Not that long ago I couldn't run 200yards without getting out of breath.Healthy mind&body =control in Biz pic.twitter.com/BQNVoZC64m— Michelle Mone OBE (@MichelleMone) December 18, 2014
"Smashed it!" she wrote alongside. "Not that long ago I couldn't run 200 yards without getting out of breath, Healthy mind & body = control in Biz."
Michelle has also been working hard on her lingerie brand. Last month with the help of Abbey Clancy, the launched a new underwear range, named Molly, to raise money for Breast Cancer Care.