Wales need a victory to secure the Grand Slam while France must win by 20 points to retain the title. Prince William will present the trophy to the eventual Six Nations champions.
WRU chairman David Pickering said: "We are delighted that Prince William will be at the Millennium Stadium on Saturday to share what I am sure will be a very special day for Welsh rugby.
"He has taken time out of an extremely busy schedule and we are delighted that he will present the RBS 6 Nations Trophy to the tournament winner."
Prince William will be attending his fourth Wales match since taking up the role of vice-patron in February last year.