Comedian Seth Rogen has defended his stance on pop star Justin Bieber, insisting the singer is "obnoxious" and "ungrateful" after his string of run-ins with the law. When the Baby hitmaker was arrested on suspicion of driving under the influence of alcohol, as well as resisting arrest without violence and driving with an expired licence following allegations of drag racing in Miami, Florida in January (14), many celebrities gave their opinion on Bieber's legal troubles, including funnyman Rogen. He took to Twitter.com the same day Bieber was taken into custody and wrote, "All jokes aside, Justin Bieber is a piece of s**t." And during an interview on U.S. late night talk show Watch What Happens Live on Wednesday (12Mar14), Rogen stood his ground and defended his decision to call out the 20 year old on his recent antics. Rogen explained, "Oh, that's because in my opinion, Justin Bieber is a piece of s**t. He seems like he's obnoxious and ungrateful and insincere and puts people's lives at danger with his horrible behaviour. And overall, he acts like a piece of s**t." In addition to Bieber's troubles in Miami, he is also facing an allegation of summary assault in Toronto, Canada, where he stands accused of hitting a limo driver during a night out in December (13).