Subject: Will the light from betelgeuse be hot?

I was reciently reading about the (galactically speaking) impending supanova 
which I read would be bright enough to make it seem like we had 2 suns in the 
sky. If this were the case.. would it be warm like the sun? And would it 
gradually get brighter when the light reached us or would it be instantly from 
night to day (assuming it reached us during our night)? And what colour light 
would it be?

Re: Will the light from betelgeuse be hot?