Hollywood star Dwayne Johnson had to cut short his honeymoon to fill in for friend and comedian Kevin Hart on "The Kelly Clarkson Show".

Johnson and his newly-wed better half Lauren Hashian were honeymooning in Hawaii, but their holiday was cut short owing to Hart's accident.

Hart was hospitalised with a major back injury over the weekend, and is recovering from a back surgery at the moment.

Clarkson explained the situation on Wednesday in a Twitter video shared by the official account of the show, reports "usmagazine.com".

"My first guest today was supposed to be actor and comedian Kevin Hart. So, as many of you know, Kevin was seriously injured in a car accident. He's OK and recovering, but because Kevin couldn't be here, one of his good friends stepped the heck up, and I love him," the singer told the audience in the video.

"His wife probably hates me," Clarkson quipped.

Johnson, who married his longtime girlfriend in Hawaii on August 18, opened up about his willingness to give up his vacation.

"When my son Kevin Hart goes down with an injury, his big daddy steps in. I did leave my honeymoon early (Lauren approved because she loves Kelly) and now me and Kelly are new best friends," he wrote on Instagram.