Sir Jimmy Savile was investigated under caution by Surrey police in 2007 over allegations of a sexual assault dating back to the 1970s.
The investigation was later dropped after the Crown Prosecution Service (CPS) said there was insufficient evidence for a prosecution, the force confirmed.
The questioning by police was already known by trustees of the DJ's charity - the Jimmy Savile Charitable Trust - but this is the first time it has been confirmed by police.
The revelations have come out on the eve on an ITV documentary which will claim Savile sexually assaulted up to 10 women when they were underage at the height of his fame.
A spokesman for Surrey police said: "In 2007, Surrey police received an historic allegation of indecent assault which is alleged to have occurred at a children's home in Staines during the 1970s.
"The allegation was investigated and an individual was interviewed under caution. The matter was referred to the Crown Prosecution Service for a charging decision who advised there was insufficient evidence to take any further action."
A spokesman for the Jimmy Savile Charitable Trust told IB Times UK: "It is well known that Surrey police investigated an allegation of underage sexual abuse against Sir Jimmy during his lifetime and determined no action should be taken against him.
"At no time was he found to have committed any such serious offence."
The ITV documentary Exposure: The Other Side of Jimmy Savile is due to be screened on 3 October.
Roger Foster, Savile's nephew, has said his family are "disgusted and disappointed" at the allegations against the 84-year-old, who died last October.
An ITV spokesman said: "This documentary is the result of an in-depth investigation into long-standing allegations of serious and widespread sexual misconduct by Sir Jimmy Savile.
"Because of the very serious nature of the claims made by several interviewees in relation to this, particular care and consideration was of course given to the decision to produce and broadcast this programme.
"The programme takes full account of the fact that Sir Jimmy is not here to defend himself against these claims."
Foster, from Goole, East Yorkshire, added: "The guy hasn't been dead for a year yet and they're bringing these stories out. It could affect his legacy, his charity work, everything. I'm very sad and disgusted."
"I just don't understand the motives behind this. I just think it's very, very sad you can say these things after someone's died and the law says you can't defend yourself when you're dead."