Kevin Hart pledged $25 000 to Hurricane Harvey relief efforts and called on fellow celebrities to do the same. File picture: Danny Moloshok/Invision/AP

Houston - Kevin Hart has made a sizable donation to flood relief efforts in Houston, and he wants some of his famous friends to do the same.

The comedian announced a $25 000 donation to the American Red Cross for victims of Hurricane Harvey. In an Instagram video posted Sunday, Hart said he was starting a celebrity challenge to donate money to the cause. Beyonce, Jay Z, Justin Timberlake, Dwayne "The Rock" Johnson and Jerry Seinfeld are among the stars he called on to make their own pledge.

"This is a serious matter," Hart said in the video. "I think the people are in bad shape and they need help. I'm going to lead the charge and step it up in this way."

While only a few stars announced donations to flood relief efforts, many have used their massive social media followings to encourage people to give what they can.

Katy Perry, who boasts Twitter's largest following at more than 103 million, urged viewers to donate while she hosted MTV's Video Music Awards on Sunday night.

AP