For Colin Farrell, it was a proud moment for him when his son James took his first steps

20-year-old James who has been diagnosed with a rare neurogenetic disorder, Angelman syndrome, was not hitting regular benchmarks as a 2.5-year-old kid which was concerning for Farrell.

"He couldn’t sit up. He wasn’t crawling. I think he was a year and a half when we took him to get really checked out, and he was diagnosed as having cerebral palsy," he told People magazine.

"It was a common misdiagnosis because it shared a lot of the same characteristics," he added.

Two weeks before James' fourth birthday his therapist came up and showed one of the James milestones.

"I knew they were working on walking. And I stood over there, and she let him go, and he just came to . . . [he pauses to collect himself] I mean, it was so profound. It was magic. I’ll never forget just the face of determination on him as he walked toward me. He took like six steps, and I burst into tears,” the actor recalled.

The Batman actor noted that parents of Angelman syndrome kids are usually told that their kids might be unable to walk, so seeing his son walk was so special for him.

"So to see those first steps was just . . . I’ll never forget it. It was so overwhelmingly beautiful,” Farrell added.

As per Mayo Clinic's website, "Angelman syndrome is a condition caused by a change in a gene, called a genetic change, causes delayed development, problems with speech and balance, mental disability, and, sometimes, seizures."