The veteran actor will play Methuselah, who the Bible records as the oldest person in the world at the time of the great flood.
He joins Russell Crowe as Noah, and Jennifer Connelly, who starred alongside Crowe in A Beautiful Mind and will play his wife.
Darren announced on Twitter: "I'm honoured to be working with the great Sir Anthony Hopkins. We just added him to the stellar cast of Noah. #methuselahlives."
Other actors signed on to the movie include Ray Winstone and Emma Watson, who will play the love interest for one of Noah's sons.
Filming is set to take place in New York and Iceland, and construction has already started on the set.
The film is expected to be released some time in 2014.