'How I Met Your Mother' Stars Perform 'Les Miserable' Musical Piece, Series Finale Spoilers [Videos]

After a nine-season run, the series finale of "How I Met Your Mother" is finally here—CBS will air the last episode on Monday, March 31.

In lieu of the finale, the cast of the hit comedy series paid a recent visit to "Inside the Actors Studio" to give a retrospective farewell, and while there, one audience made a special request. Because the popular sitcom has incorporated epic musical numbers in the series, an acting student in the audience asked Jason Segel and Neil Patrick Harris to perform a quick rendition of "Confrontation" from "Les Miserables."

"You haven't done that in a lonnng time," responded co-star actress Alyson Hannigan. Then, with little hestitation, Harris started to dramatically sing the number and Segel followed his lead.

There's no telling if fans will be treated to another musical during the series finale, which is titled "Last Forever." According to CarterMatt, a good portion of the story will be devoted to showing the next 17 years of Ted's life and the lives of his children. It will also be revealed why Ted is telling his children the story in the first place and a mystery guest star from the past is slated to make an appearance. The producers of the hit comedy sitcom also promise that the hour-long finale will leave fans with satisfaction and closure.

In a recent interview with E! News, HIMYM star Alyson Hannigan revealed that the final episode is beautifully done and admitted that she became emotional while shooting it.

"I laughed, I cried, and I was like, 'How are we going to shoot this? I'm going to be a mess!'" she said. "But it was wonderful, and it was the perfect way to go out, and I'm so grateful that we got a season nine to end the show the way it should be. It deserved this ending."

Likewise, actress Cristin Milioti also found it tough to shoot the final scene, which happened to be the same exact scene she performed during her HIMYM audition last year.

"To have that be the last thing... I could barely get through it," she shared, according to TVLine. "[It was nice] to have it come that full circle."

The one-hour series finale, "Last Forever" Part 1 and 2, is set to air on Monday, March 31, at 8 p.m. EST on CBS.

Watch a preview below as well as Segel and Harris perform at "Inside the Actors Studio."