Okay, if you’re not already watching “Fringe,” you should be. This science-fiction show is stepping into the realm of musicals, with tonight’s episode, “Brown Betty.” It airs on FOX at 9/8c.

While Walter deals with some upsetting news, he tells Olivia’s niece, Ella, a fairy tale that includes musical performances by Olivia and Agent Broyles.

Word has it that Special Agent Olivia Dunham (Anna Torv) will croon a Stevie Wonder song, and Junior Agent Astrid Farnsworth (Jasika Nicole) will belt a number from A Chorus Line.

This special musical episode is part of Fox’s sweeps week called “Fox Rocks,” with various popular shows featuring some sort of musical element. (Likewise, tonight’s episode of “Bones” involves a rock ‘n’ roll fantasy camp, though the episode is not musical.)

“Fringe” is not the first television series to delve into musical territory:

Perhaps the most famous musical episode was Buffy the Vampire Slayer‘s superb “Once More, With Feeling.” (Season 6, episode 7) [Purchase the CD and the complete season 6.]

“Scrubs” had an episode called “My Musical,” (episode 6 of Season 6), which featured a patient hallucinating that everyone in the hospital was singing. [Purchase the music here, and the season here.]

“How I Met Your Mother” celebrated its 100th episode on January 11, 2010, with a number devoted to Barney’s (Neil Patrick Harris) love of suits. [Watch the video of "Suits, the Musical."]

An episode of “Batman: The Brave and the Bold” featured Neil Patrick Harris singing, as well. [Purchase the episode.]

And who could forget “Dr. Horrible’s Sing-Along Blog,” though it was an Internet mini-series. Still VERY worth checking out, though, with the talents of Neil Patrick Harris, Nathan Fillion, and Felicia Day. [Purchase the DVD.]

FRINGE returns for a second thrilling season that will continue to explore the unexplained phenomena and terrifying occurrences linked throughout the world – known simply as “The Pattern” – in pursuit of a larger, more shocking truth.

Set in Boston, the FBI’s Fringe Division formed when Special Agent OLIVIA DUNHAM (Anna Torv) enlisted the help of institutionalized “fringe” scientist WALTER BISHOP (John Noble) and his son, PETER (Joshua Jackson), to save her partner and lover from a mind-bending death. Through unconventional and unorthodox methods, the FRINGE team imagines and tests the impossibilities while investigating unbelievable events, macabre crimes, and mystifying cases involving pyrokinesis, neuroscience, cryonics, genetic engineering, astral projection, and other fantastical theories. When the unimaginable happens, it’s their job to stop it.

Agent PHILLIP BROYLES (Lance Reddick) guides the group, while by-the-book Agent CHARLIE FRANCIS (Kirk Acevedo) and Junior Agent ASTRID FARNSWORTH (Jasika Nicole) provide support and depth to the team. Underscoring the unfolding mysteries, enigmatic Massive Dynamic executive NINA SHARP (Blair Brown) asserts that the advancement of technology is changing the world of science, and conversely, the science of the world.