How to play as Luigi in Super Mario Galaxy 2 at the beginning of the game?

I know when you get 27 or so stars in the game you can play as Luigi if you talk to him at the beginning of a level but how can you play as him at the beginning of the game? I already got all 242 stars but it was gotten by alternating between Mario and Luigi. Is it possible to play as Luigi at the beginning of Super Mario Galaxy 2? Does anybody know?How to play as Luigi in Super Mario Galaxy 2 at the beginning of the game?
As far as I know, it is not possible to play as Luigi from the beginning of the game. The closest you can get to it is by changing to Luigi at the beginning of levels or by first finishing the game (finish the final Bowser level for the first time), then changing to Luigi permanently by going into the L door on the Mario's spaceship. That is the closest I you can get to controlling Luigi in Super Mario Galaxy 2.How to play as Luigi in Super Mario Galaxy 2 at the beginning of the game?
you need 110 stars but he is playable tought out the game randomly