Secretary of Agriculture Tom Vilsack was interrupted while testifying before a Senate Finance Committee hearing on trade when Sen. Pat Roberts's (R-Kan.) cell phone began playing, "Let It Go" from Disney musical Frozen. (AP)

(This post has been updated.)

Sen. Pat Roberts (R-Kan.) is 78 years old. He’s in his fourth term. He’s the sixth-oldest senator in office. And he’s apparently a big “Frozen” fan.

The elder statesman was grilling Agriculture Secretary Tom Vilsack at a committee hearing on the merits of a massive free-trade agreement being pushed by the Obama administration. And Vilsack was in the middle of a long answer about the aggressive approach his department was taking with European nations about the need for biotechnology to reduce reliance on pesticides and about global food security.

And then Roberts’s cellphone rang next to him on the dais. And the tune of “Let It Go,” the uber-anthem by Idina Menzel from the Disney animated smash “Frozen” that has captivated 7-year-olds across the world, filled the committee room.

Vilsack stopped talking. Roberts looked sheepishly at his smartphone. “Aw, come on,” he muttered.

Then he quipped to Vilsack, “Just let it go, mister,” drawing guffaws from fellow senators, staffers and the Obama cabinet members in the room, including Treasury’s Jacob Lew and U.S. Trade Representative Michael Froman.

“Sorry about that,” Roberts added, turning off the phone and putting it away.

“Senator Roberts’s “Let it Go” ringtone is for his grandkids,” his spokeswoman Sarah Little told the Loop. “He balances it with Johnny Cash’s ‘I Walk the Line.’ He changes depending on the day.”

The senator didn’t waste the blush-worthy moment, using it to make a partisan jab:

Maybe Congress is the perfect setting for “Frozen 2”? Though we’re not convinced that the kiddos would be lining up at the box office for that sequel…