Alongside a snap of former TOWIE star Mark cradling their beloved dog, Michelle wrote that while her other half "drives her mental" he "keeps her sane" at the same time.
The actress' full message read: "Happy birthday to my husband. You drive me mental and keep me sane at the same time. So proud of you for everything you do and the person that you are. Can't wait to celebrate properly with you."
Michelle and Mark have been married for five years.
WATCH: Michelle Keegan films inside stunning bedroom at home with Mark Wright
They met in Dubai in 2012, but kept their relationship under wraps before going public at the British Soap Awards in May 2013.Mark proposed to Michelle nine months after they met and told The Mirror, "I've got now, for the first time in my life, what I've always wanted and what every boy dreams of – affection in a relationship, love, best friend, a girl I fancy… everything rolled into one."
Michelle later tweeted, "Thank you all for the lovely messages, and yes it's true @markwright_ and I are engaged! We are SO happy! Xxx."
Michelle shared the photo on Instagram
They went on to marry in May 2015 and the pair told HELLO!, "It was the day our dreams came true," while Michelle added, "Seeing Mark looking back at me as I walked down the aisle was the best feeling ever."
On their fifth anniversary on 24 May, Michelle took to Instagram with a photo of herself and Mark on their big day and wrote, "5 years ago today. Happy wedding anniversary @wrighty_ Thank you for always holding my hand."
Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.