(Michael Loccisano/Getty Images)

“Happy father’s day — or as they call it in my family, happy brother-in-law’s day.”

Ronan Farrow in a Sunday tweet that might take you a second. . . . got it? His father, Woody Allen, left his mother, Mia Farrow, 20 years ago, to hook up with Farrow’s adopted daughter Soon-Yi, now his wife. Saucy stuff from the 24-year-old State Department aide turned Rhodes Scholar, who usually tweets about Egyptian elections and third-world health, but it seems to be no hack. Mia later retweeted his message, adding, “Boom.”

Read earlier: Ronan Farrow, son of Mia and Woody, lands Rhodes Scholarship, 11/12/11

Ronan Farrow lends songwriting support to Jim Kimsey, 1/5/12