United Kingdom, Sept. 7 -- Martha Plimpton is "not ashamed" of her ADHD.

The 54-year-old actress received her diagnosis of the condition in her early 50s and has now said getting it was a "huge relief" instead of a worry as it helped explain her behaviour.

Appearing at the premiere of Task in New York City while wearing a necklace that read 'ADHD', she told Page Six: "I'm actually a late diagnosis ADHD, like millions of others.

"It was actually a huge relief to be diagnosed. So many little things fell into place and made sense that hadn't made sense before.

"I'm not ashamed and (I'm) finally free. I'm glad to be sharing my ADHD-ness with the world."

According to the US National Institute of Mental Health, attention-deficit hyperactiv...