Children living with cancer in Northern Ireland will be able to access two new state-of-the-art isolation rooms at the Royal Belfast Hospital for Sick Children.
The move brings the number of specialist rooms to ten.
They allow children who are seriously ill to be treated by specialist nurses in one area.
Boxer Carl Frampton cut the ribbon alongside a number of patients.
He told the BBC it was good to be among so many happy and positive children after a "disastrous weekend" that saw his fight with Mexican Andres Gutierrez cancelled.
"Coming up here puts things in perspective.
"You see these kids and what they are going through and their families - so what happened to me is irrelevant really."
The additional rooms will also allow more children to recover closer to home if they receive treatment further afield, such as in England.
The rooms create infection-free areas that are crucial in a person's recovery following cancer treatment.
Ross Patterson is eight-years-old and a cancer survivor. He was diagnosed with Leukaemia at the age of four.
He told the BBC that he would rate the rooms 10-out-of-10.
"They are just great and bigger than the old rooms. They have TV's and your own private shower. I am better now, but it will help other children who have to come in here. "
Ross's mother, Claire, said the rooms are a welcome addition to the Children's Cancer Unit.
"When your child is sick it is like home from home, so these rooms are big enough for an extra bed for a parent - it's just great."
Each year in Northern Ireland, there are between 50 to 60 new cases of children being diagnosed with cancer.
Overall, 200 local children use the facilities provided by the Children's Cancer Unit.
Jacqueline Wilkinson, from the Children's Cancer Charity, said: "We started to plan this around seven years ago so this has been a long time coming. And it is all thanks to the generosity of the public.
"Through fundraising these rooms were built and we are so grateful."
Dr Anthony McCarthy, a consultant paediatric oncologist, said staff, patients and families had been "crying out for these rooms for some years".
"It increases the capacity of the Children Cancer and Haemotology Unit for eight to 10 beds and that in itself is just fantastic. It is good for patients, families and staff. This is a great day."