Scarlett Johansson "kind of killed" a Christmas tradition for her kids.

Scarlett Johansson ruined a Christmas tradition for her kids

Scarlett Johansson ruined a Christmas tradition for her kids

The 37-year-old actress - who has Rose, seven, with ex- husband Romain Dauriac and Cosmo, four months, with boyfriend Colin Jost - had to explain to her daughter why the Elf on the Shelf decoration was stored away in a box.

She said: "I kind of killed the Elf on the Shelf tradition. [She] found him in the box the other day. She was like, 'Why is he in this weird dusty box?' And I was like, 'He lives there right before Christmas. That was bad."

The Academy Award winning star may have "killed" Elf on the Shelf - a game which sees an ornamental elf placed in a different household location every day during the countdown to Christmas - but she revealed that Secret Santa still remains a "competitive" tradition for her family during the festive season.

Speaking to E! Online at the 'Sing 2' premiere, she added: "We do Secret Santa. It's pretty competitive. My siblings are aggressive."

The actress - who voices porcupine punk rocker Ash in the animated jukebox music 'Sing 2' - also went on to heap praise on co-star Harry Connick Jr - noting his "buttery voice."

Her other co-star Matthew McConaughey said at the premiere that he was eager to do a third film, as long as his character Buster got the chance to sing.

He said: "There seems to be a petition going around that 'Sing 3', if we get to make one, [my character] Buster Moon has to sing. I'm with it. I'll sign it. I'm always keeping some sort of tune. I've been whistling, diddy-ing. My kids would say I sing. That's about as far as I've gotten,"