The stars of Clint Eastwood’s Jersey Boys have slammed Justin Bieber.

The legendary filmmaker is directing Erich Bergen and John Lloyd Young in the forthcoming adaptation of the hit musical about legendary 1960s group Frankie Valli and the Four Seasons.

And Erich, who plays Bob Gaudio, scoffed at the idea of comparing the Baby hitmaker’s current music to Frankie’s classics.

“I don’t know if we’re going to be singing Justin Bieber songs 20 years down the line,” Erich told MTV News.

“We may be, but I can tell you that Can’t Take My Eyes Off You, and Sherry and Big Girls Don’t Cry… how many years has it been' These songs hit in the early-to-mid 60s. We’re still singing them all over again, and I think great songs will always outlast the artist,” he added.

Erich’s castmate John, who plays Frankie in the film, noted the singer, with his distinctive falsetto, wasn’t without his own share of troubles.

And while Justin has had a string of run-ins with police in recent months, including a brief stint in jail on suspicion of DUI, John insisted comparing the two is incredibly unfair.

“Justin Bieber’s crime doesn’t even compare to this kind of crime,” John insisted. “These guys went into the slammer and did hard time. Justin Bieber peed in a bucket. Come on.”

The actor sees a stronger link to Frankie and hip-hop stars today.

“I think that’s probably a closer analogy now,” John said. “A rough upbringing, and getting huge success in music. The hip-hop world is probably more of a parallel to these guys.”

Jersey Boys is slated for US release June 20.