Taking to his Twitter.com page before stepping into the cinema, Bieber wrote: "About to surprise another theatre with the crew!! U support us so we support u. Thank U! Let's shock the world."
Usher also tweeted about the event moments later: "We surprised some fans... @ Regal LA LIVE today Never know who you'll see when you go to the movies..."
And Bieber wants to repeat the treat on Monday (14Feb11) and make this Valentine's Day one to remember.
He says, "I'm gonna take my mum out (for Valentine's Day), then in the night time, I'm actually flying out, but before that I wanna go to a random theatre that's playing my movie and just surprise them."