Super Mario Galaxy 2 Completion Reward

Craig Harris has said on his Twitter that completing Super Mario Galaxy 2 with 120 stars does not unlock another playable character this time. Luigi shows up at random points in the game in the sequel, so I wonder what the reward will be for totally completing this one?

“I can officially confirm that no characters unlock after 120 stars in SMG2. But it’s after 120 stars the game unlocks…[TWITTER OVER LIMIT]”

Neogaf