Have you ever jumped in the background of a photo and made a funny face without your friends knowing? It's pretty fun right? Especially when the photo is posted online and your friends realize that you totally photobombed their pic.
It turns out celebs like One Direction and Justin Bieber love making silly cameos in their friends pics, too! Click through to see 25 incredibly hilarious photos of your fave celebs photobombing their friends, then let us know in the comments below which photo you love most.
Justin may have been trying to act cool, but Scoot totally ruined it. :P