Despite Zayn quitting the group earlier this year, Liam still made a point of acknowledging his part in making them so successful since they were first formed on the UK 'X Factor'.
Liam wrote: "Wowwwww 5 years 5 boys what an amazing journey I couldn't thank you all ever enough and thank you Louis, Niall, Harry and Zayn for everything (sic)."
Zayn responded by retweeting the message for his own followers to see and writing "thanks bro", with a smiley face emoji.
