Bill Clinton still has a mistress: book

Bill Clinton has a blonde mistress who often visits when Hillary is not home, according to a new book.

The former US president's Secret Service detail even use the nickname "Energiser" when referring to her.

Author Ronald Kessler makes the scandalous claims in his upcoming book The First Family Detail: Secret Service Agents Reveal the Hidden Lives of Presidents.

Kessler, a former Washington Post reporter, is credited with breaking the story about Secret Service agents drinking heavily and cavorting with prostitutes ahead of Barack Obama's trip to Colombia in 2012.

Excerpts of his new book, released to the New York Post, reveal how agents waive aside normal protocols when Clinton's mistress arrives at his house in Westchester, New York, for a rendezvous.

"You don't stop her, you don't approach her, you just let her go in," a supervisor told a new agent, according to Kessler.

Hillary's security detail tells Bill's detail when the former US First Lady is coming home so he has time to avoid their paths crossing, the book claims.