Event won't work?

Just trying to mess around with the PlayerAdded event and it's not wanting to work, here is a script I tried to test it with:

game.Players:PlayerAdded(function(player)
    print(player.Name .. " has joined the game")
end)

And it doesn't work, only showing this output:

Workspace.Script:1: attempt to call method 'PlayerAdded' (a userdata value)

Help?