Watch Ricky catch Bieber Fever!
Bieber Fever swept through London as Justin Bieber hit the red carpet for the European premiere of his first film Never Say Never.
The 3D movie is all about Justin's life, from drum-playing toddler all the way to international megastar.
Hundreds of screaming fans packed in to try to get a glimpse of their hero.
It's been an amazing week for the singer. The night before he won a Brit Award for international breakthrough act and he even kissed Cheryl Cole!
Q&A session with Justin Bieber
Newsround's Ricky went along to London's O2 Arena to chat to Justin before the screening, and take part in a big question and answer session with him.
He managed to find out what the Biebster thinks of his fans, how long it takes to do his hair and his plans for the future.
At the end, Justin even led a sing-song of Phil Collins' In the Air Tonight!