Michael Loccisano/Getty
Farrow tells the magazine's Maureen Orth that her 25-year-old son with
While Farrow was with Woody Allen from 1980 - 1992 and their son Ronan was born in 1987, she admits that Sinatra was the love of her life.
"We never really split up" Farrow confesses of her relationship with the late singer, whom she was married to from 1966 - 1968.
No DNA tests have been done but Ronan was treated like a member of the Sinatra family, according to Nancy Sinatra Jr.
"He is a big part of us, and we are blessed to have him in our lives," she told Vanity Fair via e-mail.
Ronan, who is now an outspoken journalist and lawyer, responded to the report humorously on Twitter:
Listen, we're all *possibly* Frank Sinatra's son.
- Ronan Farrow (@RonanFarrow) October 2, 2013
Now judge for yourselves.
Here's what Ronan Farrow looks like today. Check out those baby blues:
Andrew H. Walker/Getty
And here's Frank Sinatra, aka "Old Blue Eyes," in his younger years:
Associated Press
Seems there is more of a resemblance than to Woody Allen:
AP Photo/Doug Mills
Here's Woody Allen and Mia Farrow as a couple in 1984:
AP Photo/Frankie Ziths
And below is Mia Farrow with Frank Sinatra on their wedding day in 1966.
Associated Press
Sinatra and Farrow had no children together during their marriage, while the actress adopted two children and had one biologically (Ronan) while married to Woody Allen.
The new Vanity Fair interview also addresses past allegations that Allen sexually abused their adopted daughter, Dylan.
In her first on-the-record comments about the incident, Dylan, who now has another name, says of Allen, "I'm scared of him, his image. I was doing it because I was scared. I wanted it to stop."
Allen still denies the allegations, his lawyer tells Vanity Fair.
Meanwhile, Allen is currently married to Soon-Yi Previn, Farrow's adopted daughter from her first marriage to Andre Previn.
The couple have been married for 16 years and have two children together.