March 30 is a special day for two seemingly totally disconnected actors: Warren Beatty (“Splendor in the Grass,” “Bonnie and Clyde,” “Reds” ) and Ian Ziering (“Beverly Hills 90210” and . . . um . . . oh, “Dancing With the Stars!”).

Beatty and Ziering share a birthday; today, Mr. Annette Bening turns 74 while Steve Sanders celebrates his 47th year on this planet.

But as proven by Six Degrees of Celebrity Birthdays, a new Celebritology feature (or possibly just a blog post I’ll do this one time; I still haven’t decided ), they are connected by more than just their date of birth.

The filmographies of Beatty and Ziering sync up, per the well-known Kevin Bacon game, via a mere four degrees: Beatty starred in “Bulworth,” alongside Isaiah Washington, Washington was on “Grey’s Anatomy” with Patrick Dempsey, Dempsey was in the HBO movie “Iron Jawed Angels” with Hilary Swank, and Swank was on — boom! — “90210” with Ziering.

But wait, there’s more. As mentioned above, Beatty starred in the 1969 classic “Bonnie and Clyde,” in which we learned that crime doesn’t pay. Or rather, it does for a while, until the criminals get killed in a gorgeously cinematic spray of gunfire.

And Ziering?

Well, he appeared in a very special episode of “Beverly Hills 90210” in which Brenda and Dylan dressed as (yes) Bonnie and Clyde, and in which we learned that dressing like a slutty witch is never a good idea at a Halloween party.

In short, birthday boys Beatty and Ziering have shared practically the same career. Sort of. In a not-at-all kind of way.

Got a suggestion for a future, equally ridiculous Six Degrees of Celebrity Birthdays item? E-mail it to me.