The representative released a statement to Eyewitness News saying, "Catherine and Michael are taking some time apart to evaluate and work on their marriage."
People magazine, citing unnamed sources, reported there had been a lot of tension surrounding their relationship, including health issues - his throat cancer and her bi-polar disorder and his son's incarceration for drugs.
Zeta-Jones, 43, and Douglas, 68, were married in 2000. They have two children.
Douglas battled throat cancer in 2010 and made headlines this summer when he spoke out about one potential cause, oral sex.
The Associated Press contributed to this report.