Some people aren’t buying the rumours about Ronan Farrow’s parentage.

In an excerpt from new memoir Sinatra and Me: In the Wee Small Hours, published by People, Tony Oppedisano writes about legendary singer Frank Sinatra.

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“I wanted the world to get a peek at the man that very few people knew,” he tells the magazine. “A man I was fortunate enough to know and become very close to.”

For several years, rumours have abounded that Mia Farrow and Woody Allen’s son Ronan, was actually fathered by Sinatra.

In 2018, Allen told New York Magazine, “In my opinion, he’s my child. I think he is, but I wouldn’t bet my life on it.”

Oppedisano writes in the new memoir, “There’s been a lot of gossip about Frank’s possibly being Ronan’s biological father, rumours I believe I’m a position to tamp down.”

He explains that Sinatra and Mia stayed friends after being married for two years, and that in 1992 he actually helped arrange a visit between the two.

“When she was beginning to have problems with Woody [Allen] she was looking for some comfort and it was like two old friends catching up,” Oppedisano says. “She was devastated and he was there to support her.”

But when it comes to fathering Ronan, who was born in December 1987, Oppedisano says that this would be near impossibly because in late 1986 Sinatra underwent emergency diverticulitis surgery and “had to wear a colostomy bag until he fully recovered.”

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He adds that Ronan’s birth date also doesn’t fit with Sinatra’s calendar at the time.

“There are only two ways Frank could have fathered Ronan, both absurd,” Oppedisano writes. “Either Mia made a secret trip to shack up with Frank in his California home with [fourth wife] Barbara present, or Frank, wearing his aways romantic colostomy bag, made a quick trip to Connecticut between his Atlantic City performances.”

He also adds, “If Ronan had been Frank’s son, Frank would have acknowledged him.”

Finally, responding to people who claim Sinatra and Ronan look alike, Oppedisano says, “People say, ‘Take a look at [Ronan]’ and I say, ‘Well, take a look at Mia at the same age.’ They look like twins. I’ve got blue eyes too and I’m not Frank’s son.”