Celebrate good times, come on! Justin Bieber and Hailey Baldwin have plenty to celebrate ... the supermodel is the first face of Levi's 501 jeans and the legacy brand celebrated what they're calling "501 Day" with a blowout bash, headlined by Hailey.

Meanwhile, Justin's back to work and celebrating a DECADE since his first single "One Time," with the help of manager Scooter Braun. Crazy, huh?! We've been worshipping Bieber since he was a little boy, basically -- his talent, his ability to captivate a worldwide audience, his smile, everything!

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10 years ago today we launched the first single for this young kid @justinbieber that I believed could change the game. We literally had to make the song ourselves outside of our label budget (which wasn’t even open) and my friend @trickystewart made the song with us as a favor. We put it out with no plan other than let’s hit the road with this guy @ryangood24 that @usher brought on and my friend @kennyhamilton who worked at T-Mobile in atl. We used YouTube and social media (never been done before at that time) to try and prove everyone wrong. @allisonjamiekaye and I met this wild man @dankanter who might be one of the top 438 guitar players from Canada and added him to the team 😂. We got a dj named @djtayjames off the college scene and off we went. @pattiemallette we were all so young but you trusted my vision for your boy and I thank you and honor you for that. 10 years later our lives have changed and that floppy haired kid has become a legend. But beyond all his achievements since ...I’m proud of the young man he has become. His heart for others is incredible and his growth at such a young age is admired. We have come so far in 10 years and so many other hits have happened (literally one right now with @teddysphotos at the top of the global charts) both in music and in life. But one thing has remained constant... @justinbieber is my family and I’m proud of him and I love him like family. #onetime #10years - watch what we do the next 10 years 😁

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