The blonde beauty first appeared to let slip the big news on 26 December (12) after referring to the director as "my hubby" in a post on the social networking site, and now Polish has also alluded to marriage with a cheeky tweet.
When a fan from Argentina sent a photo of the Blue Crush star to Polish and asked, "What do you think about this girl?" he replied, "Married it."
Bosworth re-tweeted the message on her account and also shared a photo of a birthday bouquet her man surprised her with as she turned 30 years old on Wednesday (02Jan13), writing, "What a beautiful way to start my bday! Thank you, Michael Polish."
The romantic moviemaker then tweeted, "Happy Birthday to my #1 on the #2 day of 2013. Kate Bosworth, I love you."