Justin Bieber, Chris Brown Rap on Asher Roth New Song 'Actin Up' [LISTEN]: DJ Drama and Don Cannon Host Rapper's 2013 Mixtape 'Greenhouse Effect Vol. 2'

Pop star Justin Bieber and "Fine China" crooner Chris Brown both appear on Asher Roth's new song, "Actin Up." The catchy rap tune will appear on Roth's upcoming mixtape entitled "The Greenhouse Effect Vol. 2," presented by DJ Drama and Don Cannon. Female rapper Rye Rye also provides guest-vocals on Roth's new track. Listen to Roth's recently-released "Actin Up" below!

Roth released "The Greenhouse Effect" back in 2008 - both DJ Drama and Don Cannon serve as hosts on the 2013 installment of the mixtape series. The album includes 23 original freestyles compiled by the "I Love College" rapper.

On Tuesday (June 25), Roth released the audio for his newest single "Actin Up" - featuring Bieber, Breezy, and Rye Rye:

Beliebers came out in full-force in support of the Biebs' rapping skills (Bieber begins freestyling at around the 2:15 minute mark):

Aaraa Mathialakan: "PAY ATTENTION B#TCH!! BIEBEEER IS HERE!!!!!"

Yulia Stolshtein: "F#CK!! I love this songggg it's perfect!!! Justin rapping!!!!! I am dying!!"

Lauren Banbury: "LIKE IF YOU'RE ONLY LISTENING TO THIS 'COS OF JUSTIN!!!"

Breezy's vocals follow Bieber's.

Do Mstars fans dig the new Asher Roth tune?