Photo: The Belmont High Marching Band with Jimmy Fallon at Harvard.

It’s not every Saturday that Cambridge Police will close down a portion of Massachusetts Avenue to let the Belmont High School Marching Band parade past Harvard College.

But on a gloomy Saturday afternoon, Oct. 24, the 100-strong Marauder Marching Band lined up near the intersection of Arrow Street to head up Mass Ave. with a police escort needed to keep the fans at bay.

Oh, did I mention that the Tonight Show’s host Jimmy Fallon was also there?

And while the band sounded top-notch, the thousands of cheering fans who lined the Mass Ave., Holyoke Street and Mt. Auburn Street came to see Fallon – wearing a black bow tie and sunglasses while riding in a chariot and wearing a laurel crown – named the “Emperor of Comedy” by the student social club, the Harvard Lampoon.

The students presented the former Saturday Night Live alum with the Elmer Award for Excellence in Humor along with a large check for 85 cents at the steps of its clubhouse on Bow Street. 

It was there that the band was mentioned, as one of the students told Fallon there was a mix up with the buses and his regular band, The Roots, was playing at the Belmont High football game. (Note: The game was played the night before.)

Performing the Tonight Show theme – arranged for marching band! – along with “Sweet Caroline” and “Final Countdown,” the band smartly followed drum majors Helena Kim, Gillian Tahajian and Eleanor Carlile through the crowds – screaming “Jimmy” all along the route – and the narrow side streets. The parade was halted for a few minutes as a red Mazaratti suddenly blocked the road at Holyoke Center. (It moved.)

Before the show, the band played selections at the courtyard of the Inn at Harvard with many band parents (including the chair of the School Committee).

The Marauders “replaced” The Roots, when the school received a call about a week ago from a former student who had connections with the Lampoon, which was seeking a marching band to lead the parade, said Arto Asadoorian, the district’s arts director.

If the Lampoon would pay for a couple of buses to ferry the kids to Harvard and back, then they could have their music, said Asadoorian, who came to the parade with the receipt. Band Director Paul Ketchen got the group up to speed with the new music, and it was all systems go for Saturday.

For the band, it was a thrill to play before the biggest collective crowd this year.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

“It was an out of body experience,” said Carloias, as she stood watching Fallon receiving the Elmer Award. “Everyone was friendly, and we got to take our phones and take photos.”