Caroline Flack, Simon Cowell and Olly Murs are just some of the names who took to Twitter today to send their congratulations to One Direction following the boyband’s US chart-topping success.

The quintet made history this morning by becoming the first ever UK group to enter the Billboard Top 200 at number one with their first album, ‘Up All Night.’

Harry Styles’ ex-girlfriend Caroline Flack showed she remains on good terms with the singer after posting: “Incredible news for One D!!!! HUGE news x,” whilst Simon Cowell, who signed the boyband to his Syco label, praised their army of followers, tweeting: “I couldn’t be happier for @onedirection, it is an incredible achievement. They deserve it. They have the best fans in the world.”

The stream of well-wishes continued throughout the day including messages from fellow X-Factor stars Olly Murs who excitedly wrote: 'WELL DONEEEEE!! @onedirection #1 with Debut Album in US Billboard Charts!! 1st Ever Uk Band to do it!! That's amazing stuff lads!! Ledge!!” and Alexandra Burke, who said: “Congrats to 1D... Number one album in the US!!!!! #Boooom!!!!!!!!”

The group, who announced their first headline North American tour this afternoon, also used the social networking site themselves to express their joy at their unprecedented achievement.

Niall said: “Wow! We got a #1 album in USA, you guys are incredible, thank you soooo much for buying up all night, best day of my life!,” while Louis Tomlinson added: “Actually can't believe we got a number 1 album in America. Thank you to the fans all over the world ! Big love x”