Prince Harry Britain's Prince Harry in Norfolk, eastern England, Dec. 25, 2014. Photo: Reuters

The British royal family is capping off 2014 with a scandal of epic proportions. In author Jon Conway’s play “Truth, Lies, Diana,” it is alleged that former Household Cavalry officer James Hewitt started his five-year affair with Princess Diana of Wales prior to the birth of her second son, Prince Harry, in 1984.

The play, which purports to be based on interviews, official statements and court transcripts from those closest to the late princess, including Hewitt, also hints that her former lover, not Prince Charles, might be the young prince's biological father, as many have speculated for years, the Daily Mail reports. “Diana and I started our relationship more than a year before Harry was born,” Hewitt’s character says in the play. “Now that doesn’t prove that I am his father. It’s just the … inconvenient truth,” he adds.

While Hewitt's character does not claim to be Harry’s father in the show, he does speak about his connection to the young royal. “When the journalist, who is played by Conway, asks Hewitt if he knows who Prince Harry’s father is, he pauses before answering, ‘Of course I do,’” reports the Daily Mail.

James Hewitt James Hewitt's romance with the late Princess Diana is addressed in the play "Truth, Lies, Diana." Photo: Reuters

Hewitt, 56, previously denied starting his affair with Diana prior to Prince Harry’s birth, claiming their romance began when the prince was two years of age. Recently, he is said to have called Conway's play "accurate," only to later deny the reports citing his approval. "I have not seen the script. Neither have I seen the play. I would be foolish to comment on it before doing it," Hewitt said, according to the Daily Mail

Conway said Hewitt’s line about Harry in the play is not confirmation of the prince’s paternity. “There is a startling revelation that James Hewitt makes, and he has allowed to me make it in the play,” Conway said. “That is the fact that his relationship with Diana started 18 months before Prince Harry was born. We are not saying that he is Prince Harry’s father, although the audience may take their own view on that.”

Princess Diana spoke out about her affair with Hewitt during an interview with the BBC in 1995. “He was a great friend of mine at a very difficult, yet another difficult time, and he was always there to support me,,” she said. When asked if their relationship went beyond the boundaries of a platonic friendship, Diana admitted it had. “Yes, I adored him. Yes, I was in love with him. But I was very let down,” she said.

“Truth, Lies, Diana” follows the "factional" tale of one journalist’s attempt to find out the hidden truth about Diana’s death in 1997. Some other figures depicted in the play include Piers Morgan, Paul Burrell, Mohamed Al Fayed and members the British royal family, among others. Princess Diana does not appear as a character. The show premieres at London’s Charing Cross Theatre on Jan. 9 and runs through Feb. 14, 2015.