Before Midnight Memories officially hits stores on Monday, Harry Styles, Liam Payne, Zayn Malik, Niall Horan and Louis Tomlinson will be broadcasting live to their Directioners all over the world in a seven-hour live stream event.
"1D Day is all about giving back to our amazing fans for supporting us for the past three years," Liam said in the official 1D Day press release. "When we suggested it, we never thought anyone would let us loose LIVE all day -- we cannot wait!"
So what will happen during the broadcast? MTV News has compiled a list of everything we know about 1D Day to make sure all you Directioners are fully prepared for your viewing experience.
Where To Watch 1D Day
One Direction, who will be stationed in Los Angeles during the event, are taking over the world through their broadcast in 61 countries on Saturday (November 23) via YouTube & Google+. Directioners in the U.S. can begin watching the live stream at 2 p.m. ET.
"It will be broadcast all over the world and people can watch them present for a seven hour marathon linking in to lots of shows across the world connecting with fans," 1D Day producer and director of their "Story of My Life" Ben Winston told MTV News. "And it's almost like the most amazing webcam broadcast you could ever imagine."
They're Gonna Crash Your Party
The boy band will be featuring a "One Big Drop In" throughout the live stream, which means they are going to be crashing 1D Google hangout parties all over the globe. If you want to talk to One Direction face-to-face, follow their rules: they want to see "fancy dresses, face paints and amazing backgrounds."
"It's a huge challenge to try and create seven hours of TV, and these guys aren't presenters, so they are just going to chat with the fans for seven hours and really give back," Winston said.
How To Get Involved
Fans have been put to the test in the past several weeks with several challenges, including creating their own music video, theme song and finding pictures that look like the boys. The winner will be announced on 1D Day.
During the stream, fans can use the hashtag #1DDayLive, get rewards with the Zappar app and play along with the official 1D Day quiz.
Celine Dion, Khloe Kardashian, Simon And More Will Be There!
Over the past three years, One Direction made some friends in high places, and some of them will be stopping by throughout the show. In a video posted by 1D, they revealed that Robbie Williams, Celine Dion, Simon Cowell, Kelly Rowland, Piers Morgan, The Muppets, Khloe Kardashian and many more will be making a cameo.
"We've got celebrity guests coming in, we've got a quiz that we are doing, there's competitions..." Winston said. "It's a really fun-packed day from everything from wrestlers to choirs to a house band to playing the new album. It's going to be packed."
They'll Attempt World Records Every Hour
In addition to featuring some behind-the-scenes footage of the guys, which will most likely include some shirtless shots of Harry, 1D will also be attempting to break several world records, which could get a little messy.
"We are going to try and break a world record every hour," Winston said. "For things like how many toilet rolls can you pile up in a pile."
1D Day of the Doctor
Not only are One Direction celebrating the release of Midnight Memories on Saturday, but the famed British series Dr. Who is commemorating its 50th anniversary with "The Day of the Doctor." At some point during 1D Day, Niall, Harry, Liam, Zayn and Louis will broadcast into "Doctor Who Live: The Afterparty" on BBC3.