Carrie Underwood's sons have seen her Reflection residency at Resorts World in Las Vegas, and they have strong feelings about the best part of the show.

Three-year-old Jacob and (almost) 7-year-old Isaiah don't necessarily agree on the best part, however. Underwood's youngest son says the waterfall moment that ends the show is his favorite part.

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As for Isaiah?

"Isaiah's favorite part is when I light a truck on fire during 'Before He Cheats,'" Underwood tells Good Morning America.

This moment came mid-show during the December debut, which Taste of Country was on hand to see. Underwood's aerialists/dancers grab baseball bats to recreate her music video for "Before He Cheats." That's where she famously does as the song says, and smashes her bad boyfriend's car. With the flick of a match, she ignites the Jeep each night.

Underwood reveals that her boys like watching her perform. It makes her feel good, too.

"Jacob is still a bit young to take it all in, but since Isaiah is almost seven, he's seen me on stage and on tour before," she tells the show.

Underwood's residency will resume in March and continue off and on through mid-May.

Carrie Underwood Reflection: The Las Vegas Residency Pictures

Carrie Underwood kicked off her Reflection: The Las Vegas Residency on Wednesday, Dec. 1. The show featured nearly two dozen hit songs plus a dazzling video wall and eight talented dancers who went to great heights to entertain the audience.

PICTURES: See Inside Carrie Underwood's Beautiful Post-'American Idol' Home

Carrie Underwood invested her money wisely after winning American Idol in 2005. One of her first big purchases was a 3,099-square-foot home in the well-to-do Nashville suburb of Franklin, Tenn. Underwood paid $384,000 for a luxurious 3-bedroom, 3.5-bathroom stone and stucco home in a private gated community.

The house features a library, a vaulted ceiling and lovely amenities throughout, but while it's very nice, it's certainly not the kind of home you'd picture for a budding country superstar. Underwood wound up being a huge success right out of the gate with her debut album, Some Hearts, and she sold the home in Franklin for $372,500 in 2007, when she purchased the Brentwood mansion that she would later share with her husband, Mike Fisher.