“Gossip Girl” is no longer a trendy show, but it can pack a punch. Monday night’s 100th episode floored viewers with one shocking revelation after another.

• Georgina Sparks was revealed as the Gossip Girl. Possibly.
• Blair and Louis got married  only to have the Prince’s motives revealed to be no more than a business deal. The dirty bastard.
• Blair and Dan Humphrey ran off together following the reception. Runaway Princess Bride.
• As well as Blake Lively in a dream sequence as Marilyn Monroe singing “Diamonds Are A Girl’s Best Friend.”

The plotlines can be ridiculous — Blair’s pact with God to save Chuck’s life — but the show continues to be compulsively watchable.

Executive producer Stephanie Savage, who previously worked on “The O.C.” and “Chuck,” is happy that GG hit the century mark. A sixth season seems a certainty.

It’s very hard to get to 100 episodes. “The O.C.” got to 93 episode. “‘Chuck’” got to a heartbreaking 91 episodes. 100 episodes in our industry is considered the standard of success, of achievement. So to be able to get there, especially on a serial drama, especially on a show about young people, especially in a cycle where there was a writers strike, it’s a big deal.”