One Direction Movie Trailer: Band Releases 'Best Song Ever' with New Trailer for 'This Is Us' [VIDEO]

One Direction releases the Best Song Ever.

No really, the song's title, released today along with a new trailer for 1D's upcoming 3D concert film "This Is Us," is "Best Song Ever," according to the Daily Mail UK.

Now, aren't the boys a bit cocky? Not quite, as the new video shows their humble beginnings and their life on the road.

The movie trailer, posted on the One Direction VEVO channel, has been viewed 4.3 million times already (and counting) in just less than three days.

The world-famous boys Niall Horan, Zayn Malik, Harry Styles, Louis Tomlinson, and Liam Payne launched the video teaser and trailer via a video message announcement to "Directioners" all over the planet.

Horan started, "Hi guys, it's us again. We've got a little secret we've been keeping and we want you to be the first to know about it."

And then Styles added, "We are releasing a new single. It's called Best Song Ever. It's going to be in our movie, you can pre-order it from midnight."

"We worked really hard on it and we hope you really like it. It's called the Best Song Ever," Malik followed.

Since the announcement, the 1D boys have busily tweeted the release of "Best Song Ever."

The song is co-written by Julian Bunetta, Ed Drewett, Wayne Hector, and John Ryan.

The film's new trailer, on the other hand, includes scenes from the band's tour footages.

"This Is Us" promises to be an intimate road show film about the journey that the boys take throughout their Take Me Home world tour.

Teasing teenage Directioners all over the world are a few shots of Styles and Payne...in their underwear. With footage of Payne pulling Styles' pants down on-stage.

"In one emotional scene, Zayn Malik's mother Tricia Malik is seen crying down the phone with happiness as she thanks her son for buying the family a new house," The Daily Mail UK writes.

Zayn then warns his mother to get off the phone or else he might start crying. We imagine Directioners everywhere hanging at the edge of their seats.

Best Song Ever has been made available for pre-order from June 26 midnight via www.onedirectionmusic.com, with the single available via download on July 22.

Watch the trailer for "This Is Us" and hear the "Best Song Ever" below.