Shark Week isn't working out well for Justin Bieber. 

The pop star's friend endured a nasty shark bite, courtesy of a reef shark the buds ran into while vacationing together over the Fourth of July holiday weekend.

Bieber posted a gruesome pic of pal Joe Termini's injury.

Alongside the photo, the singer wrote, "Exactly why I hate sharks they told us reef sharks don't bite."

Exactly why i hate sharks they told us reef sharks don't bite @joetermini

A photo posted by Justin Bieber (@justinbieber) on

It seems Bieber's buddy is fine though, as the heartthrob posted a tweet later, joking about the incident. 

He wrote, "Hey @joe_termini it's #SharkWeek lol"