Credit: Desiree Navarro/WireImage

Ronan Farrow’s ol’ blue eyes may provide a clue.

In an in-depth interview with Vanity Fair, Mia Farrow was asked if Ronan Farrow, long described as the only biological child of Farrow and Woody Allen, might actually be the son of on-and-off love Frank Sinatra. Farrow replied, “Possibly.”

The actress was married to Sinatra from 1966 to 1968 but continued to be his lover afterward — including when she was involved with Allen. Sinatra died in 1998. When the Vanity Fair reporter asked Nancy Sinatra Jr. about Ronan being treated as if he were a member of her family, Sinatra answered in an e-mail, “He is a big part of us, and we are blessed to have him in our lives.”

This bombshell by Farrow is likely welcome news for Ronan, who has openly cut off all ties with Allen since Allen and Mia Farrow separated following Allen’s relationship with Farrow’s daughter Soon-Yi Previn. In 2012, Ronan Farrow tweeted, “Happy father’s day. Or as they call it in my family, happy brother-in-law’s day.”

This morning, following the Sinatra news being made public (and you thought your mom was embarrassing!), Ronan Farrow wrote on Twitter, “Listen, we’re all *possibly* Frank Sinatra’s son.”