Bieber has revealed on his Twitter account that Hart will serve as Roast Master in the special, writing "This is gonna be good."
The Comedy Central Roast of Justin Bieber will air on the Comedy Network in Canada on March 30 (at 10 p.m. ET/PT).
The annual televised roast sees panellists skewering a featured celebrity with biting remarks.
In a posting on his Twitter account last month, Bieber said he's long wanted Comedy Central to roast him.
He said the channel told him he needed to provide more material — and he "worked hard" to provide it for the past year.
In his tweet about the Hart news on Monday, Bieber used the hashtags "#neverscared" and "#kindascared."