Pinter is considered Britain's greatest living playwright

"He hasn't been very well for a while. He is back in hospital," said Pinter's agent, Judy Daish.

Doctors had already forbidden the 75-year-old from attending the Nobel prize ceremony in Sweden this week because of ill health.

Pinter recorded the laureate's lecture on Sunday. It will be screened at the Nobel ceremony on Wednesday.

"He has recorded his Nobel lecture in a studio, so in order for him to have done that presumably he must be stronger than he has been," Daish added.

She did not say why Pinter had been admitted to hospital. The award-winning playwright has been battling cancer for some time.

Pinter, whose plays include The Birthday Party and Betrayal, was announced the winner of the $1.3m (�723,000) cash prize in October.