Michael Douglas and Catherine Zeta-Jones are planning to renew their wedding vows.

The couple - who have children Dylan, 13, and Carys, 10, together - separated last August after 14 years together but reconciled later in the year and now want to reaffirm their commitment to one another on their shared birthday in September.

A source told Britain's Grazia magazine: ''Michael and Catherine have been through a lot together over the last few months.

''They would love to renew their wedding vows and have thought about doing it on their shared birthday, 25 September.''

The Hollywood couple have sought therapy to help get their marriage on track and now have a number of systems in place to help maintain their relationship.

The source explained: ''Counselling has been a massive help for Catherine and Michael. They've been working on different ways to express feelings - including daily journals.

''They only show them to each other if things get bad - it's a way of giving them an outlet.

''They're going to take one month apart a year - they've realised how important it is to take a breather and allow themselves time to take stock.''