Duhamel spent much of his youth in the town and eventually pursued his undergraduate studies at Minot State University.
Thousands have been evacuated from the North Dakota town since raging waters damaged a significant section of the city's infrastructure, including a home owned by Duhamel's sister.
The star, who is married to Fergie, took to his official Twitter page to express relief that his sister escaped physical harm in the floods, writing: "She & her family are safe; which ultimately is what really matters."
While his sister escaped unharmed, Duhamel has learned that his childhood home was destroyed in the raging floods.
Duhamel told ET Online: "This little girl sent me a picture today on Facebook with a red arrow pointing to one of the houses that's under water and it's my house that I grew up in. My heart is with them."
The Transformers: Dark of the Moon actor has now teamed with the Minot Area Community Foundation and the American Red Cross in an attempt to raise awareness for those in need.
Duhamel has stressed the importance of offering assistance to those displaced by the disaster, saying in a press statement: "I spent the first 22 years of my life in Minot and still have family living there, including my sister and her family who have lost their house to floodwaters.
"Minot will always be home to me, and it breaks my heart to see the devastation the city and its residents are going through. People from Minot are strong and come together in a time of need, and I know they'll get through this. But with everyone's help, we can make it easier for them to restore their lives and the surrounding Minot area."
The American Red Cross is currently accepting donations for those wishing to contribute to the Minot relief efforts.
Transformers: Dark of the Moon is now playing in US and UK cinemas.
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Watch Josh Duhamel open up about the Minot floods below:
Watch a trailer for Transformers: Dark of the Moon below: