1. Gemma Collins – TOWIE.
Then: Gemma joined TOWIE for its second series in 2011.
Now: Gemma has disappeared and in her place is "the GC", who has significantly bigger hair.
2. Sam Faiers – TOWIE.
Then: Sam was an TOWIE original when she started the show in 2010.
Now: Once she left the show, Sam did Celebrity Big Brother, created a fitness empire, and gave birth to her first child.
3. Mark Wright – TOWIE.
Then: Mark was more known as being a playboy that wore incredibly low cut v-neck t-shirts.
Now: You can now find Mark living out wedded bliss with his wife Michelle Keegan and presenting the spin-off show for Take Me Out.
4. Lucy Mecklenburgh – TOWIE.
Then: Lucy was more obsessed with fake tan when she first joined the cast of TOWIE.
Now: Lucy runs her own fitness empire.
5. Lauren Goodger – TOWIE.
Then: Lauren's storylines in TOWIE revolved around her on-off relationship with Mark Wright.
Now: Lauren has lost an entire FOUR STONE and has released a fitness DVD.
6. Vicky Pattison – Geordie Shore.
Then: Vicky was the first person to enter the Geordie Shore house. In her time on the show, she even got engaged.
Now: Vicky now has her own TV show, Judge Geordie, and is the reigning queen of the I'm A Celebrity jungle.
7. Gary "Gaz" Beadle – Geordie Shore.
Then: From the first episode of Geordie Shore, we learned that Gaz was a player with a dick the size of a sky remote that was nicknamed "the parsnip".
Now: You can still find Gaz living up to his playboy reputation in the Geordie Shore house, and he also occasionally strips off with The Dreamboys.
8. Charlotte Crosby – Geordie Shore.
Then: Charlotte fell in love with the parsnip when she first joined Geordie Shore in 2011.
Now: Charlotte is one of the cast originals still doing Geordie Shore, which has just finished its 11th series, but she also has a book, fitness DVDs, and a Celebrity Big Brother winner title to her name.
9. Holly Hagan – Geordie Shore.
Then: Holly bounced back into season two of Geordie Shore with hair brighter than the sun.
Now: Holly now takes her health and fitness seriously, releasing books about her weight loss. She also did a clubland remix of Milkshake, which was incredible, no matter what anybody else says.
10. Spencer Matthews – Made in Chelsea.
Then: Spencer was known for being the resident love rat on Made in Chelsea.
Now: He's sorted out his hair and got ripped at the gym.
11. Binky Felstead – Made in Chelsea.
Then: Binky was the most down-to-earth star of Made in Chelsea, not to mention she was bloody hilarious.
Now: Binky is still on the show, and has her own clothing collection on the side.
12. Ollie Locke – Made in Chelsea.
Then: Ollie was most known for his long and glorious hair while on Made in Chelsea, as well as coming out with some of the funniest one-liners.
Now: After a short hiatus and a stint on Celebrity Big Brother, Ollie is back on the show. You could say he looks slightly different now.
13. Louise Thompson – Made in Chelsea.
Then: Louise came onto Made in Chelsea as Spencer's friend with benefits.
Now: After ditching Spenny, Louise is now in a longterm relationship with co-star Alik, who she met while filming in New York for the show.
14. Chantelle Houghton – Big Brother.
Then: Chantelle went into the Celebrity Big Brother house as a fake celebrity housemate. She went on to win the series.
Now: Chantelle now tends to keep a lower profile. She has a daughter with ex-fiancé Alex Reid.
15. Josie Gibson – Big Brother.
Then: Josie went into the Big Brother house in 2010. She won the series with 77.5% of the vote, which is the highest percentage in Big Brother history.
Now: Josie is now a qualified personal trainer (and still absolutely hilarious).
16. Nikki Grahame – Big Brother.
Then: Nikki was one of the stand-out housemates of Big Brother in 2006. She's probably best known for her line "WHO IS SHE".
Now: Nikki went back into the Big Brother house in 2015 as part of a task. She was also a columnist for Celebrity Big Brother 2016.
17. Leona Lewis – X Factor.
Then: Leona was the first woman to win the X Factor, which she did in 2006.
Now: Leona left Simon Cowell's record label Syco and released an album in 2015 called I Am.
18. Shayne Ward – X Factor.
Then: Shayne won X Factor in 2005, going on to release four albums.
Now: Shayne works the cobbles of Coronation Street these days, and also won an NTA for best newcomer for his role.
19. Cheryl Fernandez-Versini – Popstars: The Rivals and X Factor.
Then: Cheryl competed in Popstars: The Rivals in 2002, earning herself a spot in girlband Girls Aloud.
Now: After over a decade in the industry, there's not much Cheryl hasn't done now. She has a successful solo career and has been a judge on X Factor multiple times.
20. Will Young – Pop Idol.
Then: Will won Pop Idol way back in 2002, beating Gareth Gates in the final.
Now: Will released a new album, 85% Proof, in 2015, which debuted at number one in the UK charts.
21. Calum Best – Love Island.
Then: In the early-mid noughties, Calum appeared on reality shows such as Calum, Fran and Dangerous Danan and Love Island, which he went on to win.
Now: Calum went into the Celebrity Big Brother house in 2015, finishing in third.