Seinfeld star Jason Alexander is refusing to autograph memorabilia for collectors who track him down and hound him for signatures.

The actor has taken to his page to vent his frustration after regularly being approached by "creepy" opportunists who ask him to sign "bundles of stuff" during his time off.

He writes, "There are an increasing number of occasions, like the ones I recently experienced, where collectors are waiting for me with bundles of stuff at airport terminals, or hotels or restaurants. Now, I never fly or stay at hotels under my professional name - nor do I ever announce that I'm on a particular flight or at a particular hotel. So, when I get off a plane, usually traveling with family or on business - and a group of collectors are there with piles and no good explanation for how the hell they knew I'd be there - that to me is a bit stalker-y (sic). It's creepy. How do these people know where I am and what I'm doing? I ask, but they don't answer the question.

"So, I put out the message that the people who stake out those arenas will not get what they want from me. It is an inappropriate place and time."

However, Alexander is adamant he will always try to give his signature to genuine fans who send him mail, come to his plays, or bump into him on the street.

He adds, "When I'm performing and I exit the venue, I'm happy to spend as much time as it takes to meet people and sign or whatever. And there are plenty of legitimate addresses on the Internet for people to write me... I almost always respond. Some things do fall through the cracks, but I try. I've even been known to respond positively in a restaurant or on the street, if I can."