Justin Bieber turns 18 years old today! It's a big milestone for the star, who was just 15 when his hit "One Time" put him in the spotlight. His career has continued to soar, but his relationship with Selena Gomez has also made headlines. The musical duo first stepped out publicly as a couple at Vanity Fair's 2011 Oscar party and since then have been happy to share PDA, pose on red carpets together, and get cozy on the beach.
Click through to see Justin's sweet moments with girlfriend Selena as we celebrate his big birthday!