Ms. Rachel and Mr. Aron are seeing rainbows in a brand new light these days.

For Rachel and Aron Accurso, the married co-creators behind the global children’s phenomenon Ms. Rachel, the colorful subject of their new single “I Love a Rainbow” became an opportunity to go bigger, musically and visually. The playful bossa nova track is the first preview of their debut album, I’m So Happy, due Sept. 25, and its new music video — premiering exclusively on Billboard — finds the pair surrounded by Colorado mountains, polychromatic scarves, chalk-covered sidewalks and plenty of play.

But let’s not mistake all of that joy for simplicity.

The music video features an extended version of “I Love a Rainbow,” complete with a new bridge, a sweeping string section and additional live musicians. For the Accursos, expanding a song already familiar to Ms. Rachel families meant finding a way to make its world feel even bigger.

“We wanted to expand it,” Aron tells Billboard. “We wrote a new bridge and we added a big string section and more live musicians, which feels expansive.”