The upcoming threesome episode on “Gossip Girl” seems to be getting everyone’s knickers in a twist, even before the much-anticipated episode of the scandalous TV show about rich New York teens airs on Monday.

The TV watchdog group the Parents Television Council says the “3SOME” tryst is “reckless and irresponsible” in view of the “impressionable teenagers” that it says are the show’s main target , and has urged affiliates of the CW network not to air it.

Fans of the show however, seem to be more concerned about trying to figure out which of the fabulously rich, beautiful young things  — now out of high school and supposedly at college — will be involved in the three-way hookup.

Judging by the bed-hopping enjoyed so far by the characters on the show,  pretty much any of them could be persuaded (or maybe tricked?) into a brief menage a trois,  although we’re betting that bad boy Chuck (Ed Westwick) and scheming Blair (Leighton Meester)  will be playing a major role.

Like all publicity ,  good and bad, the PTC warning may have the opposite effect in whetting the appetite of lapsed “Gossip Girl” fans to the scandalous story line.

As Britney Spears sang in her recent No. 1 single “Three” (on the same subject) “Three is a charm, Two is not the same.”

“Gossip Girl” is currently getting an audience of about 2.2 million a week, and although the CW as a whole is aimed at women between the ages of 18-34, the network says the median age of “Gossip Girl” viewers is 27 years old.

Try telling that to your teens.