'Thanks for going above and beyond for my birthday,' she wrote.
'I am honestly so LUCKY to have you. The fact that everyone around me can see just how happy you make me, MAKES ME EVEN HAPPIERRRRR! #bestbirthdaypresent #iloveyou.'
Erin and Mick have been dating since last year.
Coincidentally, Erin shares the same birthday – April 13 - as Married At First Sight’s Cyrell, who recently went public with her relationship with Erin’s ex, Eden.
Taking to Instagram on Saturday, Cyrell, 30, shared a loved-up pic of herself and Eden standing in front of her tiered birthday cake.
Anyone else think Erin and Cyrell’s pics are creepily similar..?