Humanitarian and all-around superachiever Ronan Farrow reportedly hasn't been on speaking terms with his dad Woody Allen for decades.

So no love was lost when he tweeted Sunday: "Happy father's day -- or as they call it in my family, happy brother-in-law's day."

Ronan's equally do-gooding mom (and Woody's ex), Mia Farrow, then added fire to the burn by retweeting the message, adding the word "Boom."

The longtime Woody-Mia relationship went "boom" in 1992, following news that the director was having an affair with the daughter Mia and world-class musician Andre Previn adopted.

Five years later, Woody and that adopted daughter, Soon-Yi Previn, tied the knot. Now 76, the director is still married to Soon-Yi, who is 35 years his junior. Always the butt of dirty or at least awkward jokes, the pair are often seen together on the red carpet.

If boy-genius Ronan (he entered Bard College in Massachusetts at the age of 11), wants to get technical, Soon-Yi was never, legally, Woody's stepdaughter. But we get his point…

Image courtesy of Mia Farrow/Twitter Supplied by WENN.com