ET went behind the scenes of Underwood's epic new music video for "Something in the Water," which required 16 choir members, 12 dancers, three costume changes and a custom-built tank of recycled water to create a stunning dance spectacle.
"We took it in a direction that was probably not what most people would think," Underwood said. "We just made it joyful and happy and uplifting."
Nearly 10 years after winning American Idol, Underwood has had 18 No. 1 hits and "Something in the Water" has had the biggest debut of them all, selling more than 125,000 copies in its first week. The video for the first single from her Greatest Hits: Decade #1 premieres Wednesday on her Twitter page.
"She was such a trooper," said director Raj Kapoor, who enlisted help from So You Think You Can Dance choreographer Travis Wall. "She loved how the dancers moved and interacted with her."
"I think we just wanted to match the energy and for things to be really beautiful," said Underwood.
The 31-year-old country singer announced her pregnancy in September.
This will mark the first child for Underwood and her husband Mike Fisher, 34, a professional hockey player for the Nashville Predators.
Watch the video for clips from the video and an Idol throwback.
Underwood's Greatest Hits: Decade #1 comes out Dec. 9.