"My wife says I don't have time for friends and that is true. It is difficult to make friends. I hardly have any," Khan told reporters at his Mumbai residence.

The actor, who turned 44 on Monday, said he only makes friends while filming a particular movie but then "moves on".

"We are all so busy working, you have friendships when you are working together and creating a product like a film together," he said.

"Then, you move on to the next product and you make new friends there."

But that doesn't mean Khan has no friends at all.

"I have a good relationship with those that I work with, maybe that is why they work with me," he said.

The actor, who has wrapped up shooting for director Karan Johar's ‘My Name is Khan’ said 2009 had been a tough year for him after a shoulder injury kept him out of action for two months.