The country star's brother-in-law had to smash the vehicle's window when Underwood and her husband Mike Fisher realised the doors had locked behind them as they said goodbye to relatives at the curbside, with their son Isaiah and the couple's two dogs inside.

At the time, she tweeted, "When your dogs manage to lock themselves, all your stuff & the baby in the car & you have to break a window to get in #whatarethechances".

The Before He Cheats singer recalled the frightening moment during a recent chat on Chicago's US 99.5 radio station, saying, "We were at the airport, the car was running, the radio was on, the air conditioning was on, our family kind of came to see us off. As you do, you get out of the front seat and you shut the door so you can turn around, so you can get your luggage out.

"Immediately, one of the dogs jumped up on the little control panel on the door, and I heard the thing click. I was like, 'The door's locked, the door's locked, the door's locked!'

"We were trying to jimmy-open the car door. Nobody had a hanger. I was trying to get the dogs to come back over and do the same thing and unlock the door."