Los Angeles, Aug 7 (IANS): Actor Mark Wahlberg has asked pop singer Justin Bieber to be a nice boy and focus on his career.

The 42-year-old-singer-turned-actor, who was jailed for assault as a teenager, also warned the "Baby" hitmaker to stop smoking weed, reports contactmusic.com.

"Justin are you listening? Don't be so naughty, yeah?" he said during a web chat with The Sun newspaper.

"Be a nice boy, pull your trousers up, make your mum proud, and stop smoking weed, you little b***h.

"He's a teenager living in a different day and age. I was in prison before I got a record out and I don't think he's been to prison. He's a nice enough kid and you're going to be a teenager. But if you're being a teen in the spotlight, you're going to be criticised for it.

"This career can be short lived - you might as well be the best you can while you're doing it," added Wahlberg.

Wahlberg is also planning to work with the 19-year-old singer on a film and may even get behind the mike again.

"Justin and I were talking about doing a movie, which could still happen.

"We have a great script, which could be a vehicle for him to make his debut in movies, then maybe we could do something for the soundtrack," Wahlberg said.