Anderson Cooper: why so not serious on CNN last night? Blame it on the Depardieu. (ANDREW KELLY/REUTERS)

Anderson Cooper’s RidicuList, a lighter-side-of-the-news staple of his program on CNN, got so ridiculous last night that it finally got the better of him.

During a pun-filled segment devoted to Gerard Depardieu’s recent urinating-on-a-plane incident, Cooper gamely stifled laughter while pumping out commentary that involved phrases like “an actual thespian actually thes-peein’” as well as a particularly clever play on words that involved Depardieu’s role in “La Vie en Rose.” (That movie was about Edith Piaf. You can probably guess where that one went.)

But at the 2:30 mark in the video below — when Cooper says the cleaning crew should “thank their lucky stars it wasn’t Depar-doo” — the distinguished journalist once hailed for his investigative reports during Hurricane Katrina starts giggling like a preteen girl with braces and a vicious Justin Bieber crush.

Watch below and see. It’s something to behold.