And how old is the Canadian star turning? The big 1-8! Time really flies - it's hard to believe he's already eighteen.

Justin's birthday is going to be a big event. Beliebers all over the world took over Twitter to announce the big day, and they're even trying to break a world record for him! (Check it out HERE.) Today's going to be a great day for Justin and tons of people are going to be talking about it.

We're sending a big happy birthday to Justin! 

Check out these two videos of Justin on Ellen. First he makes his big birthday announcement, and then he gets his special 18th birthday gift from Ellen.