Harry Styles, Zayn Malik, Louis Tomlinson, Liam Payne and Niall Horan each arrived at Alexandra Palace in the capital to kick off their busy week with a signing for their new hardback, Where We Are.
Sporting various shades of black, grey and blue, the five boys looked laid back and trendy, while also showing off their combined collection of tattoos.
Ladies' man Harry flaunted his numerous inkings by wearing a simple grey T-shirt and Zayn gave fans a glimpse of his body art by rolling up the sleeves of his denim shirt.
Niall, Liam and Louis decided to dress a little warmer than their two other bandmates by donning cosy hoodies and a sweatshirt. And what with our freezing UK weather, we don't blame them!
The five pop stars were swarmed by fans during the singing, many of whom were so overwhelmed by meeting their favourite group that they burst into tears.
But that's nothing that One Direction aren't used to!
After a jam packed few hours and greeting tonnes of Directioners, Niall tweeted: "Long day! Just did a book signing , was great to see you guys again! Thank you for waiting for us in the cold ! Really appreciate it! Xx"
The boys are also currently promoting their new single 'Diana', which has already received a great response from fans across the world, despite only just being released this week.
And one of those fans happens to be Justin Bieber, who praised the group on their track via Twitter.
Early this morning, Justin wrote: "that new 1d song diana is well written well done boyzzzzzz"
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Watch the video for One Direction's 'Story Of My Life' below.