Academy award-winning actress Charlize Theron and Sean Penn are reportedly dating.

CNN host Piers Morgan confirmed their relationship in a blog post for The Daily Mail's Event magazine, after he attended the 53-year-old actor's Help Haiti Home gala on 11 January.

"I walked over to Sean's table, where he was sitting with new girlfriend Charlize Theron," Morgan wrote. "'I'm so glad you two have got together,' I said, 'Sean's a great guy.'"

"'I know,' she smiled, putting her hand round his shoulder," he added.

Reports that the couple are dating started when the South African beauty and Penn were clicked together vacationing in a Hawaiian beach on 30 December.

Meanwhile, at the gala, among the items being auctioned off was a Jeff Koons sculpture made out of 67 guns, Penn previously owned.

"I'm a self-proclaimed Alpha male who owns 67 firearms. But I've had my mind changed about guns by a strong woman, a beautiful South African woman," he reportedly told the audience. "I don't need these cowardly instruments of violence and destruction, none of us do."

"At 2am, Sean came over, and bear-hugged me," Morgan concluded. "'Congrats on a great night,' I said. 'And congrats on Charlize too.' He laughed. 'She's a keeper, that's for sureā€¦ well, I'll do my best to keep her anyway!'"

Penn was married to Robin Wright and Theron, who won an Oscar for Best Actress for Monster in 2003, has been single since breaking up with Stuart Townsend in 2010. She has often been pictured with her son Jackson, whom she adopted in May 2012.