Colin Farrell's four-year-old son suffers from a rare form of cerebral palsy.
The Irish actor has revealed that youngster James was born with Angelman Syndrome, a genetic disorder which affects only 1 in 12,000 people and leaves its victims barely able to walk or talk.
Angelman Syndrome also causes frequent fits and seizures, but sufferers tend to have a smiling, happy demeanour.
Farrell said: "With my son the only time I'm reminded that there is something different about him - that he has some deviation of what is perceived to be normal - is when I see him with other four-year-olds.
"Then I go, 'Oh yeah', and it comes back to me. But from day one I felt that he's the way he's meant to be.
"I am incredibly blessed to have James in my life. He has shown amazing courage and he is an incredibly happy boy despite everything he has faced."
James took his first steps just weeks ago, leaving his father weeping with pride. ( FF )