In Forgetting Sarah Marshall, British pop star Aldous Snow is shown singing about global warming. His fictional band Infant Sorrow performs the environmental anthem “We’ve Got to Do Something,” which urges people to act before Earth is harmed further.
The joke comes from the contrast between the song’s earnest message and Aldous’s extravagant, self-absorbed rock-star persona. The performance appears on television near the beginning of the 2008 comedy, introducing Aldous as Sarah Marshall’s new boyfriend and as a celebrity with a deliberately ridiculous public image.
Aldous Snow is played by Russell Brand, who later reprised the character in the 2010 spin-off Get Him to the Greek. Another song associated with the character is “Inside of You,” a sensual Infant Sorrow number. The environmental song is sometimes remembered simply as a climate-change gag, but the film presents it specifically as a global-warming-themed anthem.