Bill Murray.Getty Images

The 64-year-old actor really dislikes working with youngsters in his movies but has made an exception for 11-year-old Jaeden Lieberher, who he appear alongside in his latest comedy movie 'St. Vincent' and admits the star is "more professional" than the majority of older actors he's worked with.

He said: "Most kid actors should be taken out and shot, let's face it. And their parents too.

"Yet this kid [Jaeden Lieberher] was more professional than most of the actors I've worked with. He was completely prepared and he has a wonderful mother and father who keep him normal.

"He never became a movie-star brat."

Bill's rare praise of a child actor has certainly worked wonders for Jaeden as the veteran actor helped to get the youngster a part in his latest movie, an untitled Cameron Crowe romantic-comedy which is also set to star Bradley Cooper, Rachel McAdams and Emma Stone.

When asked if he would be prepared to work with Jaeden again, Bill replied: "I already have. I was making a movie with Cameron Crowe after I finished this one and Cameron asked me what I thought of him.

"I said, 'I don't like kid actors.' Three days later, I had to call him and say, 'OK, this kid's good.' The next day, Cameron hired him."

But Bill admits he is very selective when it comes to choosing his own roles and refuses to have an agent because they used to show him so many "crap" scripts.

He added to Metro newspaper: "Agents don't get paid if you don't work, so they're constantly jamming stuff in your face – mostly stuff from other clients in their own agency.

"I remember saying, 'Please don't ever give me another script written by these people. Ever.' Because there are some writers in Hollywood who just churn out crap."