Actor Seth Rogen attends the American Comedy Awards in New York
Actor Seth Rogen attends the American Comedy Awards in New York, April 26, 2014. REUTERS/Eric Thayer

Justin Bieber has responded to Seth Rogen’s continued verbal attacks on him with a passive-aggressive tweet.

Rogen has been blasting his fellow Canadian for months, starting with a tweet in January in which he reacted to Bieber’s DUI arrest with “All jokes aside, Justin Bieber is a piece of sh**.”

He explained the tweet in March when he appeared in “Watch What Happens Live” talk show, telling host Andy Cohen, “He seems like he’s obnoxious and ungrateful and insincere and he puts people’s lives in danger with his horrible, horrible behaviour.”

He didn’t stop there.

On Monday, the 32-year-old “Neighbours” star was a guest star on shock jock Howard Stern’s radio show, in which he recalled his first meeting with the 20-year-old tween heartthrob.

“He’s a good example of someone you meet, who you think you’re going to hate him, and then you get to hate him as much as you thought. You meet him, and he meets up to every one of your [bad] expectations of how you hope he will be,” he told Stern.

He explained that the first time they met was on a German talk show, where he was asked by one of Bieber’s people to come out of his dressing room to meet Bieber.

“And it was weird, I was like, Sure, I’ll meet him. So I went outside to meet him and he was acting like I asked to meet him! It was very nonchalant, ‘You man. Sup.’ And I’m like, ‘What the f***, I don’t want to meet you. Don’t act all nonplussed to meet me I didn’t want to meet you! I was totally cool with not meeting you!’

“But I was like, fine, I wouldn’t have said anything. I was like, ‘Hey, he’s a bit of a mother******. He’s young, the kid’s a d***.”

And in a separate interview with “Today Show,” Rogen added, “I don’t know anyone who likes Justin Bieber.”

Finally, Bieber has responded to his insults with what appears to be a passive-aggressive way of telling Rogen that not everyone would submit to him.

Seth Rogan sorry I didnt bow down when I asked 2 meet u was probably a bit shy and didn't want to be over the top but still. love ur movies.

— Justin Bieber (@justinbieber) May 8, 2014

Rogen (not Rogan, as Bieber has misspelled it), hasn’t responded yet, though it’s likely that he would be launching another attack of his own.