Sky Ferreira's rocker boyfriend Zachary Cole Smith has taken full responsibility for the couple's headline-grabbing drug arrest last year (13), insisting he regrets messing up his girlfriend's music career.

The stars were pulled over by New York police in September (13) and taken into custody after cops allegedly found heroin and ecstasy in their car, which did not belong to them.

They were slapped with drug possession charges, and Ferreira, who was on the cusp of hitting the big time, subsequently admitted the legal woes had derailed her career as she had lost contracts over the incident.

DIIV frontman Smith has now spoken at length about the arrest, admitting his "stupid" behaviour will always cast a shadow over both his and Ferreira's futures in the industry.

He tells, "Basically I just was stupid. I f**ked up, and it was entirely my fault, and I f**ked up my girlfriend's life.

"She literally didn't do anything wrong. She basically was just a passenger in the car with a person who was out of control for a minute. She got in deep s**t... Her career got really f**ked up because everybody thought she was a drug addict, which she's absolutely not. That's the worst part of it for me, that I really f**ked her over."

And the arrest has also negatively impacted on Diiv's career. Smith adds, "I feel like there's all this weird mythology that sort of surrounds me, and it distracts from the purity of the band. If somebody mentioned Diiv, they wouldn't hum the song, they'd be like, 'Oh yeah, the guy who got pulled over driving a stolen car with heroin in it'. I really hate that."