Charlie Simpson: There is a certain demographic of people, who are now in their early 20s, to whom Charlie Simpson has always been credible. As one third of Busted, Simpson - who made big eyebrows cool before Cara Delevingne was into double figures - released two sterling, though not exactly critically revered, albums. While the band were still on top of their game, Simpson had an existential crisis over his own credibility and quit to focus on his post-hardcore alt-rock band Fightstar. Against all odds, their debut was cited as "one of the best British rock albums of the past decade" by Kerrang, and they're still going strong today. Though Simpson has risked the reputation he's built up over the past decade by rejoining Busted. We're delighted.

Ariana Grande: In fact, Ariana Grande is one of several children's TV stars whose music career has proved successful. Of all her contemporaries though, Grande - who rose to fame playing Cat Valentine on Nickeloden series Victorious - has the most impressive credentials. Her second album, My Everything, featured the likes of The Weeknd, A$AP Ferg and Childish Gambino, and was one of Gigwise's albums of 2014.

Sky Ferreira: Though Ferreira technically fits the bill for a place on this list, the blame for people's misconceptions lies entirely on us, not her. Because she was known as a model for IMG, and (perhaps deliberately playing into societal prejudice) used a topless photo of herself on the cover of her debut album, people initially balked at her career. There was no legitimate basis for this derision though, and the strength of the album proved that.

Adam Lambert: Auditioning for a talent show always seems like such a good idea at the time - if you're talented and/or attractive enough, it's a quicker, easier way of getting known in the music industry. Unfortunately, once you've got that leg up, everyone around you is pretty much waiting for you to fall. After finishing as runner-up on American Idol, though, Lambert began touring as the temporary lead singer of one of the biggest bands of all time - Queen. With his powerful, operatic voice and flamboyant showmanship, that partnership is still going strong. Plus, his solo work packs a mighty punch too.

Lana Del Rey: It didn't help that she already had a fairly mediocre album under her real name, Lizzy Grant - people are always suspicious of any attempt at reinvention - but it was Del Rey's shaky performance on SNL, with just one single under her belt, that caused people to write her off as a one-hit wonder destined to fizzle out before she'd even really begun. Two brilliant, brooding albums and hundreds of impressive live performances later, she's one of the biggest musicians on the planet.

Justin Timberlake: JT, bless him, has gone through about six different mildly embarrassing phases. After appearing on TV talent show Star Search as a child, he was a member of Disney variety show The Mickey Mouse Club. As it turns out, he was in pretty great company - Britney Spears, Christina Aguilera and Ryan Gosling were also members - but it wasn't critically renowned. Then, he was then a member of boyband NSYNC. Since then, he's released some of the greatest singles of the 21st century ('Cry Me A River', 'SexyBack', 'Senorita', 'Mirrors'...) and started a career as an impressive actor.

Trent Reznor: It's hard to believe the Nine Inch Nails frontman was ever anything other than an exceedingly well-respected lead singer in one of the most innovative and influential acts ever... Unfortunately, he started out as a member of an 80s new wave covers band called Option 30.

Haim: They might have topped BBC's Sound of 2013 list, but Este and Danielle Haim still had to prove that they were better than the manufactured pop group Valli Girls in which they made their start. It's probably safe to say they've done that.

Drake: He might be best known at this point for his four impressive albums - sorry, mixtapes - but Drake was originally one of the stars of Canadian teen drama Degrassi. Drake played the wheelchair-bound (after he got shot fairly early on) Jimmy Brooks for seven series of the angsty TV show, but still managed to shake off the squeaky-clean image to become one of the most successful rappers of recent years.

Justin Bieber: The pre-pubescent 'Baby' singer was a teen heart-throb, then he was a teenage delinquent, and now he's an actual musician. With the help of singles 'What Do You Mean' and 'Love Yourself', Bieber transformed into a singer it's OK to like non-ironically.

Zayn Malik: The former One Direction member is yet to actually release any of his solo music, but given the label he's signed to, and the collaborations he's teased, we suspect it's going to take sceptics by surprise. Plus, though Malik himself might disagree, One Direction have always been a pretty solid pop band anyway.