While the detainee's claims have yet to be verified, he says he met bin Laden several times prior to the Sept. 11, 2001 attacks on the United States.
Basing his information on a contact, the detainee tells the BBC, "In 2009, in January or February I met this friend of mine. He said he had come from meeting Sheikh Osama, and he could arrange for me to meet him."
The detainee added of his contact, whom he said was a Mehsud tribesman, "He helps al Qaeda people coming from other countries to get to the sheikh (bin Laden), so he can advise them on whatever they are planning for Europe or other places.
"The sheikh doesn't stay in any one place. That guy came from Ghazni, so I think that's where the sheikh was."
The BBC, which said it was unable to identify the detainee, said they interviewed him twice in November, both times in the presence of a Pakistani interrogator.
Former CIA analyst Bruce Reidel told the BBC the detainee's story should be investigated.
"The entire Western intelligence community, CIA and MI6, have been looking for Osama Bin Laden for the last seven years and haven't come upon a source of information like this," he said.
"So if it's true — a big if — this is an extraordinary and important story.
"We know Osama Bin Laden is alive. We know that he is living somewhere in the badlands along the border with Pakistan and Afghanistan.
"What is extraordinary about this story is we have someone who has come forward and said, really for the first time, 'I met with Osama Bin Laden and I had the opportunity to met him again in the recent past'.