To celebrate Justin Bieber becoming an adult and blowing out 18 candles, check out Billboard.com's rundown of the singer's 18 most memorable moments so far, and tell us what you think about our choices in the comments section.
Young Justin Stops By the Billboard Office (August 27, 2009)
Back when he was just a 15-year-old rising star, Bieber stopped by the Billboard offices to perform an acoustic version of "One Time" and talk about how he was just a "regular kid." "I started YouTube after I was in a singing competition," Bieber explained at the time. "It turned out that people started liking it…so I just kept posting more videos."
The Biebs: Welcome To 'My World' (Nov. 17, 2009)
YouTube star Justin Bieber was officially introduced to the world with his "My World" EP, which featured singles like "One Girl" and "One Less Lonely Girl" and an appearance by his pop mentor, Usher, on the track "First Dance." The album was filled with inspiring takes on young love, and tween girls were quickly at the Biebs' mercy.
A Star is Born: "Baby" Video Released (Feb. 19, 2010)
Sure, Bieber had had his share of breakout singles before "Baby" was released -- who doesn't remember "One Time" or "One Less Lonely Girl"? But the video for "Baby," set in a bowling alley and featuring Ludacris, was a game-changer for the young Canadian star, and helped him reach a new level of ubiquity. 711 million YouTube views later, we're still singing "Baby, baby, baby, OOOOH."
Justin Bieber Scores His First No. 1 Album (March 31, 2010)
Bieber fever officially arrives when "My World 2.0," featuring singles like "Baby," "Somebody To Love" and "Eenie Meenie," notches Bieber his first No. 1 album on the Billboard 200, selling 283,000 copies in its first week, according to Nielsen SoundScan. In the two years since then, Bieber has scored two more No. 1 full-lengths: his "Never Say Never" remix album and his "Under The Mistletoe" holiday set.
Take Justin Home! Bieber Dolls Hit Stores (Dec. 4, 2010)
Since it's so hard to get the real Justin Bieber to come home and hang out with you, merchandise company Bravado and The Bridge Direct, Inc. offered the next best thing: singing dolls sporting the adorable likeness of the teen superstar. After the first wave of Bieber dolls flew off the shelves before the 2010 holidays, a new, "real hairstyle" collection went on sale the following summer.
Justin and Selena Hold Hands, Millions of Teenage Hearts Break (Feb. 6, 2011)
The Green Bay Packers were the big winners on Super Bowl Sunday in 2011, and the big losers were every girl pining after Justin Bieber, who was shown holding hands in public for the first time with his long-rumored girlfriend, pop star Selena Gomez, in Santa Monica. The two have been a confirmed item ever since, free to run amok and crash weddings between music video shoots.
Bieber Immortalized by 'BasedGod' Lil B (February 8, 2011)
Cult rapper Lil B is known for his hip-hop odes to random celebrities (see: his tracks "Miley Cyrus" and "Bill Bellamy), but there was something special about his track "Justin Bieber," which features the chorus "Bieber, bieber, bieber, bieber… Justin, justin, justin, justin." Although Lil B claims that "Everybody know that Justin Bieber is my cousin," the jury is still out on that one.
Big Screen Star: 'Never Say Never' Hits Theaters (Feb. 11, 2011)
"Never Say Never," a 3D feature film that chronicles Justin's beginnings and features a whole mess of concert footage, arrives at local multiplexes in February 2011. The flick took in $30.3 million in its opening weekend, good enough for a No. 2 debut.
Justin and Usher Team Up For Grammys Performance (Feb. 13, 2011)
Bieber may have lost the Best New Artist Grammy to Esperanza Spalding in 2011, but the singer delivered one of the ceremony's most memorable performances when he performed alongside his mentor, Usher. After playing an acoustic take of "Baby," Bieber developed a taste for dance-fighting, and took on some ninjas during a rendition of "Never Say Never."
Justin Bieber Shot and Killed!… On 'CSI' (Feb. 17, 2011)
Bieber's second appearance on the CBS hit "CSI" will surely be his last, since the teen star's character (not so wisely) fired a handgun at an officer during a standoff with police, and was promptly, spectacularly gunned down. Don't worry, Beliebers -- Justin's fine. But where's the Emmy?
The Haircut Heard 'Round The World (Feb. 21, 2011)
Where were you when you heard that Justin Bieber's signature swoop haircut was no more? The pop star lopped off his locks for charity last February, going for a more mature look just before his 17th birthday.
Justin Bieber Frozen In Time as Wax Figure (March 15, 2011)
Not every teenager gets immortalized with an official Madame Tussauds wax figure, but then again, Justin Bieber was never an ordinary teenager. Dozens of screaming fans were on hand last February when Bieber's wax clone was unveiled, and the man himself was in London to give his replica a hug.
Bieber Crashes 'SNL' with Tina Fey (May 7, 2011)
During his first appearance as a musical guest on "Saturday Night Live," Bieber performed tracks off "My World 2.0" and appeared in a pair of skits with host and "SNL" alum Tina Fey. Bieber showed off his comedic chops in a sketch about a schoolteacher (Fey) who has inappropriate fantasies about her young student, Jason (Bieber). "His smile is like watching a baby bunny sniff a tiny flower," Fey's character gushed.
Justin Bieber Named Fan Favorite at BBMAs (May 22, 2011)
The Biebs won Billboard.com's first-ever Fan Favorite Award at the 2011 Billboard Music Awards, shimmying to the stage in a gold suit after kissing his girlfriend, Selena Gomez. "Every day is like, crazy to me, because I see so many people and I get to make so many people smile and make people happy…I want to thank my fans for being so amazing," Bieber told the crowd.
All I Want For Christmas Is… A Mariah Carey Duet (Nov. 1, 2011)
"Under The Mistletoe" represented a lot of big achievements for the Biebs -- his first holiday set, another No. 1 album, and, of course, collaborating with Busta Rhymes on a re-imagining of "Little Drummer Boy" -- but the lasting milestone from the album will likely be Bieber's duet with Mariah Carey on a new version of her classic, "All I Want For Christmas is You." The "SuperFestive!" duet finds Bieber working in a lower register; after all, manager Scooter Braun admitted that on the "Mistletoe" album, "vocally, his balls have dropped."
Lil Bieber Spits His "Otis" Freestyle (Nov. 2, 2011)
For those who thought the Biebs was just a pop phenom, check out his freestyle over the beat of The Throne's "Otis," which he performed during a visit to the Power 106 radio station in November. Watch your back, Drake -- you're not the only Canadian rapper with some clout.
Baby, Baby, Baby, No: Bieber Beats Paternity Suit (Nov. 16, 2011)
Our hearts collectively skipped a beat when news broke that a paternity lawsuit had been filed by a 20-year-old woman who claimed that the Biebs was the father of her three-month-old baby. Justin and his legal team vehemently denied the claim, and within two weeks of the suit being made public, the case was dismissed.
Justin Gives Back To The Kids on 'Ellen' (January 4, 2012)
Bieber showed off his charitable side during a visit to Whitney Elementary School in Las Vegas last December, in a segment that ran on "Ellen" the following month. The singer not only met with students and delivered a special performance -- he bestowed the school with a $100,000 check, as well as $100,000 worth of toys for its students. The normally rock-solid Biebs even shed a tear during the segment, but then again, we all did, too.