"These people on Facebook, they're not your friends," says William Shatner, addressing Jimmy Kimmel's late-night viewers in a recently aired faux PSA.

The comedian has declared this Wednesday, Nov. 17 "National Unfriend Day" -- a pretend holiday on which he hopes all Americans will stop and go through their Facebook accounts to weed out random acquaintances and old classmates with whom they're not truly friends.

"You want to know who your friends are?" he explains. "Post a status update that says 'I'm moving this weekend and I need help.' The people that respond? Those are your friends! Everyone else isn't."

In preparation for NUD, Kimmel has drafted his own official Declaration of Indefriendence. 'Late Night with Jimmy Kimmel' regular, Uncle Frank, read the formal document on the air last week.

And the host has brought a string of guests into the studio to endorse the idea. Lisa Kudrow stopped by for a deadpan monologue about what real friendship is (she'd know, since she was a Friend -- get it!?) in honor of NUD. Check out her clip after the jump.

By all means, this Wednesday, if you're thinking of cutting some ties, feel free to participate in NUD and tell us whose unfulfilling "friendship" you plan to drop. First, behold Kimmel's announcement (with Shatner's endorsement) here: