Charlotte Church says becoming a mother has made her even more determined to help raise money for a state-of-the-art Children's Hospital for Wales.
The singer and television host launched a campaign to raise £4m to provide vital equipment and facilities for the next phase of the hospital in Cardiff.
The hospital's first phase has treated over 15,000 youngsters since 2005.
Church said having baby Ruby made it "a hundred times" more important for her to help children.
The second phase of the hospital, which will be built adjacent to the first phase building, will include children's operating theatres, a teenage cancer unit, a children's eye clinic and a private garden for sick children and their families.
The star, who grew up in Cardiff, urged people to start fundraising to help provide the equipment for the new building.
Part of the £4m needed will fund an "open" MRI scanner.
The £1.5m scanner has no sides and a parent can lie next to their child during the scan, minimising the need for sedation.
After touring the wards, Church, who is a patron of the Noah's Ark Appeal, which raises funds for the hospital, said: "It's amazing to see how the parents cope.
"When you have a child of your own it makes it so much closer to home.
"If Ruby was ever ill, which touch wood she'll never be, just to know there would be a children's hospital that's absolutely state-of-the art, that you wouldn't have to travel to England for, to have it right here in Wales, would make any parent sleep well at night."
Church cuddles Logan Donegan and chats to his mother Rhian
Church gave birth in September at the home in St Brides Major, in the Vale of Glamorgan, she shares with rugby player boyfriend Gavin Henson, who was looking after Ruby during Church's visit to the hospital.
She said she was hoping Wales and Ospreys star Henson would join her as a patron of the Noah's Ark Appeal in a bid to raise awareness among rugby fans.
"It's just so important. If you see the difference from the new wards to the old wards, it's just unbelievable and we really, really need to have a state of the art Children's Hospital for Wales," she said.
"When I look at what these parents go through I feel absolutely blessed, so lucky to be able to go home to my baby who's in good health and doesn't have to come to hospital for months at a time."
Ms Church also spent time cuddling children and speaking to their parents, who welcomed the drive to improve facilities in the new hospital.
Rhian Donegan, 19, from Bargoed, whose six-month-old son Logan needs a liver transplant and has been at the hospital since he was born, said: "I have been on all the wards and some are not so nice. The wards in the new building are really nice, you have got a cubicle of your own."
The singer at the Wales-France Grand Slam decider
Natasha Hardacre, also from Bargoed, whose daughter Lacey, five-months, was born premature, said: "This new hospital is really important to us as Lacey is always going to need surgery."
Simon Atkins, from Abercynon, whose 12-year-old daughter Zoe has Rett Syndrome, a neurological disorder, said: "It's great Charlotte's here - a really nice surprise. Although I think Zoe would prefer to see Gavin!"
Building on the second phase of the hospital is planned to start in the autumn, with work taking place in phases to allow patients in the existing building to be moved before it is demolished and replaced.
The £43m second phase building is being funded by the assembly government while its running costs will be met by local health boards and Health Commission Wales.