Grant Hackett and Candice Alley.

Marriage breakdown ... Grant Hackett and Candice Alley in 2010.

Olympic gold medallist Grant Hackett and his wife Candice Alley have separated.

"I can confirm media speculation this morning that Candice and I have separated," Hackett said in a statement to News Limited online.

"I want to be dignified in my approach to everything and ensure the children's needs are paramount and put first.

"I wish Candice every success. It is my hope that everybody can respect the process and be kind to all parties involved as it is a very difficult time."

The couple wed in 2007 and have two children together, twins Jagger and Charlize.

Hackett retired in 2008. That same year he signed a four-year deal with the Nine Network to be part of their sports coverage.

Singer-songwriter Alley has released two albums - Colorblind in 2003 and Candice Alley in 2009.

AAP