The Hunger Games: Mockingjay -- Part 2" -- even when they're trying to whistle a tune from their own movie.

During the "Mockingjay" panel at San Diego Comic-Con on Thursday, castmates Jennifer Lawrence, Josh Hutcherson, and Liam Hemsworth all tried -- and adorably, hilariously failed -- to replicate the series's iconic Mockingjay whistle tone. But the trio, and the rest of their castmates on the panel, just could not nail the four-note melody, which was memorably used by Rue and Katniss in the first film, and brought back throughout the rest of the series as a Mockingjay rallying cry of sorts.

In video of the incident uploaded by Screen Crush, the actors all try numerous times to get the whistle down right, but to no avail. At one point, Hutcherson imitates crickets, which panel moderator Conan O'Brien joked was a frequent sound during his stand-up routines.

Hemsworth comes closest to whistling an actual song, but as X-Files" theme. Still in the science fiction genre, still not quite right.

Check out the hilarious video below, and try not to get too sad when you realize that this is the last "Hunger Games" panel at Comic-Con ever.

"The Hunger Games: Mockingjay -- Part 2" hits theaters on November 20.

[via: Screen Crush]

Photo credit: Eric Charbonneau/Invision/AP