Not every candidate would welcome an endorsement from a guy known as “Meathead.”

But when that guy is Rob Reiner — Meathead in the 1970s television hit All in the Family — you take the endorsement and run.

Reiner, the 62-year-old actor, director, comedian and political activist, and one of the most connected people in Hollywood and Democratic politics, came out for Hillary Rodham Clinton in September.