Zeta Jones and Michael Douglas at children's hospital

Actors Catherine Zeta Jones and Michael Douglas have visited a Cardiff hospital to boost its fundraising campaign.

The Swansea-born actress officially opened the Children's Hospital for Wales back in 2006.

The Hollywood couple's return coincides with the 10th anniversary of the original Noah's Ark Appeal. They are touring the hospital facilities.

The charity needs to raise a further £7m to build an intensive care unit, operating theatres and wards.

The pair met patients and their family members at the hospital as part of an official tour.

Catherine Zeta Jones is a patron of the Noah's Ark Appeal - set up to raise funds for the hospital.

In 2005, the couple donated a five-figure sum to the charity.

The actress said: "I know how important it is to have a designated children's hospital here.

"I'll do as much as I can to help. I'm so proud of all the staff and doctors who have worked so hard.

"And just walking round the hospital with Michael today, to see the relief and gratitude on the parents' faces as they take care of their little ones, I thank you all for doing such a wonderful job."

She added: "It's hard to believe there was never a designated children's hospital in our country [Wales]."

The star said the couple were "used to running to the hospital, like any parent" with their children.

She said that, for example, their daughter had knocked out her two front teeth during her first week at school, while their son had needed minor medical hospital treatment in Spain.

Catherine Zeta Jones and Michael Douglas arriving at the hospital in Cardiff

Michael Douglas said a children's hospital was a "necessity" for Wales.

He said he found the nurturing offered by the staff to the children at the hospital, and the parents, was "quite stunning".

He said: "I think Wales should be very excited about the future in the terms of the children's hospital - I think it's going to come a long way, to continue.

The first phase of the project included two 25-bed medical wards and one 16-bed paediatric cancer ward.

It cost £9m to deliver, with £4.5m provided by the assembly government and £4.5m raised by Noah's Ark.

The hospital's second phase will have operating theatres, a teenage cancer unit, an eye clinic and a private garden for patients and their families.

The £54.3m unit is being funded by the assembly government while its running costs will be met by local health boards and Health Commission Wales.

In addition, Noah's Ark has committed to raising £7m to support equipment, including an MRI scanner and vital equipment for the new intensive care unit.

The £1.5m scanner has no sides, meaning a parent can lie next to their child during the scan, minimising the need for sedation.

The demolition will begin in January 2011 with the main construction starting in August 2011. It is hoped the full development will be completed in 2014.