More than a thousand people turned out for the 16th annual Old Town Riverfest on Saturday, and the grand marshals for the parade were chart-topping pop duo Karmin — one half of which is Old Town native Nick Noonan.

Though Noonan is now a big-time pop star with legions of fans, he’s still an Old Town boy at heart, greeting old high school classmates and family friends as he and his fiancee and musical partner in crime, Amy Heidemann, rode through downtown Old Town and later met with people in Riverfront Park.

“It’s always important to come home,” said Noonan, who graduated in 2004 from Old Town High School, and is the son of Mike and Judy Noonan. “And plus I hadn’t been home in a while so it was an excuse to come home and hang out.”

Noonan and Heidemann helped lead the Saturday morning parade, riding in an antique bright red convertible alongside the Old Town High School and University of Maine marching bands, OTHS sports teams, community organizations, businesses and many others. Crowds of young fans screamed for the couple, including a number of preteen girls, holding signs emblazoned with the Karmin logo and the word “Cheerio!,” a lyric in their hit single “Brokenhearted.”

Despite the drizzly rain and mid-50s weather, a line of hundreds stretched around the gazebo at Riverfront Park for a meet-and-greet with Noonan and Heidemann. The pair posed for photos and gave out lots of hugs and autographs, including signing the cover of the latest issue of Rolling Stone magazine, which Heidemann graces along with British megastar Adele. Readers voted for which women they wanted to appear on the cover of the issue, which is the “Women Who Rock” edition, and Heidemann won out against many other pop and rock heavyweights.

“We were up against some amazing women and somehow we scored the cover,” said Heidemann.

Karmin’s Epic Records debut EP, “Hello,” came out last May and has already sold over one million copies, with lead single “Brokenhearted” reaching No. 16 on the Billboard singles chart and No. 1 on the Billboard dance chart. Karmin expects to release their first full-length album later this year, which they are finishing up with producer L.A. Reid.