Frank, whose most recent work includes the script for Wolverine, will rewrite an earlier draft written by British playwright Michael Lesslie.
"I'm rewriting Assassin's Creed right now, and what I love about it is that I've never adapted a video game before and it has its own set of challenges," said Frank. "Especially in the world of re-writes, I love trying to do something completely different if I can."
Frank previously earned an Academy Award nomination for his adaptation for Out of Sight. His work also includes credits on Dead Again, Minority Report, Flight of the Phoenix and Get Shorty.
Assassin's Creed will hit theaters June 19, 2015. The film stars Michael Fassbender who is also attached to the project as producer.