The countdown to the series finale of "How I Met Your Mother" continues this Monday with an all-new episode that looks to be hilarious as Barney struggles to pick out a suit to wear on the morning of his wedding.

Based on last week's episode, "Rally," it appears that Barney is not going to be so hungover for his big day afterall. However, in the next episode, "Vesuvius," he will wrestle with choosing the perfect suit for his wedding, which could send him over the edge.

A promo video teases flash-forwards of Ted and the Mother and Robin wearing a hockey jersey.

CarterMatt also reveals that the episode will be a bit nostalgic as it will reference "The Wedding Bride," the movie that was a part of Ted's history with Stella. Later on, Ted banned it out of rage because he was publicly shamed by Stella's other boyfriend.

According to CarterMatt, the official synopsis of the upcoming episode states: "On the morning of the big wedding, Lily and Robin are going to have a fight, and Barney will totally freak out about which suit to wear. In the meantime, the gang will watch a movie that Ted has forbidden them to see."

Lucy Hale will reprise her role as Robin's sister Katie, Chris Kattan will return as Jed Mosely, and Jon Heder will guest star as Narshall, reports the Hollywood Hills.

"Vesuvius" is set to air on Monday, March 3, at 8 p.m. EST on CBS.

Watch a preview below.