On October 24, Krystal Jung, the visual centre and lead vocalist of K-pop girl band F(x), turns 27 –making her five years younger than idol sister Jessica Jung . September marked the 12th anniversary of Jung’s debut, and she’s been on a tear ever since, with a number of hit dramas and films added to her repertoire recently too, including Netflix’s latest K-drama, Sweet and Sour . It seems safe to say that even at her young age, she’s achieved a lot . Here are five things you should know about Krystal Jung ahead of her big day. She was in a Shinhwa music video back in 2000 Almost 10 years before her debut in F(x), she featured in a music video with Shinhwa – the legendary first generation K-pop boy group also produced by SM Entertainment. Only six years old at the time, it’s hard to recognise her face at first, but eagle-eyed fans will still be able to spot which one she is! Why Koreans are only allowed to buy one Chanel bag per year  when krystal was 6 y/o, she was featured in Shinhwa's Wedding March MV #childmodelkrystal pic.twitter.com/kCCxyzMkrT — krystalpics (@krystaIplcs) January 11, 2016 Aside from Shinhwa’s Wedding March music video, Krystal also featured in a handful of adverts when she was younger, including one for Lotte alongside Moon Embracing the Sun actress Han Ga-in. After her parents allowed her to join SM Entertainment, and after three and half years of hard work as a trainee, Jung was finally able to debut as a lead vocal with F(x). 6 K-pop stars who smashed stereotypes through their music She is fluent in English – and her educational background explains it If you’re a fan of either Krystal or her sister Jessica , you’ll have seen the pair chatting in English with each other on many occasions. This shouldn’t come as a surprise, however, as she in fact holds dual nationality in both South Korea and the US. Krystal was born in California and lived in the state until the year 2000, when she first came to Korea and was directly scouted by SM Entertainment alongside her sister Jessica – at ages five and ten respectfully! After she and her sister decided to come back to Korea, they both attended Korea Kent Foreign School, which is popular for its curriculum and strong language department. How Squid Game’s Jung Ho-yeon became an overnight icon She is allergic to apples These days it seems that plenty of idols have weird allergies – and our dear Krystal is no exception. According to Hype, Krystal has an apple allergy. However, apparently dishes featuring cooked apples are okay, and on an episode of F(x)’s Koala , she said she also still liked to eat green apples. She is a good friend of Park Shin-hye’s Of all of her hit dramas, The Heirs might be the one that caught the attention of K-drama fans the most. And just as Krystal and Park Shin-hye showed off their great chemistry in the drama, it seems the two continue to have a great friendship off screen too. 4 Korean actresses who almost became K-pop idols 150526 f(Krystal) & Park Shin Hye = 51st Baeksang Arts Awards (cr.on pic) #51thBaeksangArtAward2015 pic.twitter.com/ZRGpjrIskq " — oyés, jung (@soujgs) May 27, 2015 In 2015, when F(x) released their new single 4 Walls , Park posted a screen shot of herself listening to the song with the caption of “I love you Krystal”. Then in 2016, Park shared a photo of F(x)’s concert on Instagram, commenting “I love you Bona” (the name of Krystal’s character in The Heirs ). Park even showed her love in the classic way that all supportive idols do – by sending a snack car to Krystal on the set of The Bride of Habaek , which Krystal duly posted a photo of to her socials. Are Blackpink’s Jisoo and football star Son Heung-min dating? She has some controversial food obsessions – like mint chocolate Mint chocolate and Hawaiian pizza are two of the more controversial foods in South Korea. Folks will look at you quizzically if you admit a love of either of them – not least because they’re thought of as inauthentic. Well guess what? It turns out Krystal loves to eat mint chocolate – and she’s not too proud to admit it. In fact she’s talked about it several times on screen, including on Jessica & Krystal – US Road Trip. Want more stories like this? Sign up here. Follow STYLE on Facebook , Instagram , YouTube and Twitter .