Song You Need To Know: Justin Bieber Featuring Ludacris, 'Baby'

Last week we showed you an acoustic sneak preview of Justin Bieber's "Baby," the first single off his upcoming My World (Part II). Even in its stripped down form, it was a classic breakup jam; a tear-stained love letter to a girl who didn't recognize the good thing she had right in front of her.

Now we get the full studio version of "Baby," complete with a verse from Ludacris. If you find the references to other songs (like Jay Sean's "Down") and all the "oh!" ad libs familiar, it's because they're two staples of Tricky Stewart and The-Dream, who wrote and produced the song.

The Luda verse is somewhat nostalgic, with the Atlanta rapper recalling his first love. It dovetails nicely; Bieber singing about first love as it happens, while Luda looks back on it fondly.

My World (Part II) is due out in the spring.

+ Listen to Justin Bieber's "Baby," featuring Ludacris, here.