The movie star has been praying for the safety of family and friends in his hometown ever since a severe flood warning was issued last week (ends24Jun11) while he was promoting new film Transformers: Dark of the Moon in Russia.
Duhamel revealed his sister's house had been claimed by the floods and now he has learned his childhood home has been swept away.
He says, "The house that I grew up in as a kid, the girl that lives in that house sent me a picture on Facebook with a red arrow pointing at it, and, literally, all you can see is the roof."
Duhamel now plans to head back to Minot once he has finished promoting his new blockbuster - to help those in need.
He tells USA Today, "What I'm doing is I'm raising awareness and I'm trying to raise as much money as I can to help restore the city. People are taking people into their houses that they don't even know. They're incredibly resilient and they'd never ask for help but I'm not afraid to."