The Late Late Toy Show succeeded in capturing the hearts of the nation with the appearance of cousins Scott and Grace Lowe from Athlone.
This time last year, Grace (6) was undergoing bone marrow treatment for leukemia.
Her first cousin, Scott (8) gave her the bone marrow transplant.
"They're double cousins, and Grace's other siblings weren't a match. They're best friends," said Scott's mum Arlene on the Late Late Toy Show.
Speaking to Ryan Tubridy, Scott said that he underwent the treatment because he wanted to save his little cousin's life.
"I wanted to save her life.
"I was scared going in for an operation. I felt really happy (that I saved her life)."
The young rugby fan was surprised by Rob Kearney, Sean O'Brien and Tadhg Furlong who came bearing gifts.
"This is a real life hero right here. What you have done, you are the real hero. We are really proud of you," Rob Kearney told Scott.
Watch the heartwarming video above.
Rachel Coyne from Donard in Co. Wicklow had the crowd on their feet at the Late Late Toy Show when she performed a heart-warming rendition of ‘Never Enough’ from ‘The Greatest Showman’.