Celebs build buzz for Justin Bieber's new song

Mariah Carey, Kylie Jenner and Ariana Grande are helping countdown to Justin Bieber's new song. Photo / Twitter

Justin Bieber is enlisting the help of his celebrity friends to promote his upcoming single, What Do You Mean?

The countdown to the single's release kicked off on July 30 when Bieber tweeted a picture of a clock and "30 DAYS" to his 66 million followers.

Bieber's celebrity pals have now taken over the countdown to build buzz before the song's release on August 28.

What Do You Mean? will be the first taste from Bieber's upcoming fourth album, due for release in September. It's been three years since Bieber released album No.3 - Believe.

30 days pic.twitter.com/oaKvaxamsx

— Justin Bieber (@justinbieber) July 29, 2015

American Idol host Ryan Seacrest started the celebrity countdown campaign.

"Alright here we go. Good news. Big news. In 30 days the single called What Do You Mean? is coming out. So, start the countdown clocks," Seacrest said in a video on Twitter.

What Do You Mean @RyanSeacrest? #30DAYS pic.twitter.com/YRbFQVnljb

— Justin Bieber (@justinbieber) July 29, 2015

Next up was Aussie actor and Bieber look-alike, Ruby Rose. She sat in a gondola with a sign that read "29 days" and posted the snap to Bieber's Twitter and Instagram accounts.

What Do You Mean? @RubyRose #29days pic.twitter.com/puCJzS18Cb

— Justin Bieber (@justinbieber) July 30, 2015

Other celebs who have helped out the 21-year-old popstar include Mariah Carey, Kylie Jenner, Halsey and The Fat Jewish.

What Do You Mean? @JKCorden #28Days pic.twitter.com/BFtmV6wnk5

— Justin Bieber (@justinbieber) July 31, 2015

Even @MariahCarey is excited. #WhatDoYouMean pic.twitter.com/d0qAVpULI0

— Justin Bieber (@justinbieber) August 1, 2015

What Do You Mean? @JBALVIN #27DAYS #27Dias pic.twitter.com/Z4mgj0qZRa

— Justin Bieber (@justinbieber) August 1, 2015

What Do You Mean?!?! @lildickytweets #26days pic.twitter.com/BeOJTm9ey0

— Justin Bieber (@justinbieber) August 2, 2015

What Do You Mean? @KylieJenner #25DAYS pic.twitter.com/zC2tVtcUYC

— Justin Bieber (@justinbieber) August 3, 2015

When my big bro @SHAQ can't spell my name. Lol pic.twitter.com/WB2e7EMaSl

— Justin Bieber (@justinbieber) August 4, 2015

What Do You Mean? @trvisXX #24Days pic.twitter.com/pCO6JU8Az1

— Justin Bieber (@justinbieber) August 4, 2015

What Do You Mean? @AshBenzo #23Days pic.twitter.com/VQ7O8ucCxX

— Justin Bieber (@justinbieber) August 5, 2015

Singer Ariana Grande, who's shared a stage with Bieber, is one of the select few who've heard the song.

What Do You Mean? @ArianaGrande #22DAYS pic.twitter.com/pG9qEP4FaF

— Justin Bieber (@justinbieber) August 6, 2015

"Yes, I've heard it... yes, it's fantastic," she said on Twitter.

What Do You Mean? @FATJEW #21DAYS :) pic.twitter.com/HmLUnesjG2

— Justin Bieber (@justinbieber) August 7, 2015

What Do You Mean? @halsey #20Days pic.twitter.com/dYyQorzj3K

— Justin Bieber (@justinbieber) August 8, 2015

What Do You Mean? @BigSean #19DAYS pic.twitter.com/wdaz5TFo57

— Justin Bieber (@justinbieber) August 9, 2015

The rest of the world will have to wait until August 28.

- WENN