I'm willing to go out on a limb here and guess that most stories of kindness do not begin with drug addicted celebrity bad boys. Mine does.

His name is Robert Downey Jr.

You've probably heard of him. You may or may not be a fan, but I am, and I was a fan in the early 90's when this story takes place.

It was at a garden party for the ACLU of Southern California. My stepmother was the executive director, which is why I was in attendance without having to pay the $150 fee. It's not that I don't support the ACLU, it's that I was barely twenty and had no money to speak of.

I was escorting my grandmother. There isn't enough room in this essay to explain to you everything she was, I would need volumes, so for the sake of brevity I will tell you that she was beautiful even in her eighties, vain as the day is long, and whip smart, though her particular sort of intelligence did not encompass recognizing young celebrities.

I pointed out Robert Downey Jr. to her when he arrived, in a gorgeous cream-colored linen suit, with Sarah Jessica Parker on his arm. My grandmother shrugged, far more interested in piling her paper plate with various unidentifiable cheeses cut into cubes. He wasn't Cary Grant or Gregory Peck. What did she care?

The afternoon's main honoree was Ron Kovic, whose story of his time in the Vietnam War that had left him confined to a wheelchair had recently been immortalized in the Oliver Stone film Born on the Fourth of July. I mention his mobility because it played an unwitting role in what happened next.

We made our way to our folding chairs in the garden with our paper plates and cubed cheeses and we watched my stepmother give one of her eloquent speeches and a plea for donations, and there must have been a few other people who spoke but I can't remember who. Then, Ron Kovic took the podium, and he was mesmerizing, and when it was all over we stood up to leave, and my grandmother tripped.

We'd been sitting in the front row (nepotism has its privileges) and when she tripped she fell smack into the ramp that provided Ron Kovic with access to the stage. I didn't know that wheelchair ramps have sharp edges, but they do, at least this one did, and it sliced her shin right open.

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The volume of blood was staggering.

I'd like to be able to tell you that I raced into action; that I quickly took control of the situation, tending to my grandmother and calling for the ambulance that was so obviously needed, but I didn't. I sat down and put my head between my knees because I thought I was going to faint. Did I mention the blood?

Luckily, somebody did take control of the situation, and that person was Robert Downey Jr.

He ordered someone to call an ambulance. Another to bring a glass of water. Another to fetch a blanket. He took off his gorgeous linen jacket and he rolled up his sleeves and he grabbed hold of my grandmother's leg, and then he took that jacket that I'd assumed he'd taken off only to it keep out of the way, and he tied it around her wound. I watched the cream colored linen turn scarlet with her blood.

He told her not to worry. He told her it would be alright. He knew, instinctively, how to speak to her, how to distract her, how to play to her vanity. He held onto her calf and he whistled. He told her how stunning her legs were.

She said to him, to my humiliation: "My granddaughter tells me you're a famous actor but I've never heard of you."

He stayed with her until the ambulance came and then he walked alongside the stretcher holding her hand and telling her she was breaking his heart by leaving the party so early, just as they were getting to know each other. He waved to her as they closed the doors. "Don't forget to call me, Silvia," he said. "We'll do lunch."

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He was a movie star, after all.

Believe it or not, I hurried into the ambulance without saying a word. I was too embarrassed and too shy to thank him.

We all have things we wish we'd said. Moments we'd like to return to and do differently. Rarely do we get that chance to make up for those times that words failed us. But I did. Many years later.

I should mention here that when Robert Downey Jr. was in prison for being a drug addict (which strikes me as absurd and cruel, but that's the topic for a different essay), I thought of writing to him. Of reminding him of that day when he was humanity personified. When he was the best of what we each can be. When he was the kindest of strangers.

But I didn't. Some fifteen years after that garden party, ten years after my grandmother had died and five since he'd been released from prison, I saw him in a restaurant.

I grew up in Los Angeles where celebrity sightings are commonplace and where I was raised to respect people's privacy and never bother someone while they're out having a meal, but on this day I decided to abandon the code of the native Angeleno, and my own shyness, and I approached his table.

I said to him, "I don't have any idea if you remember this…" and I told him the story.

He remembered.

"I just wanted to thank you," I said. "And I wanted to tell you that it was simply the kindest act I've ever witnessed."

He stood up and he took both of my hands in his and he looked into my eyes and he said, "You have absolutely no idea how much I needed to hear that today."

Dana Reinhardt is the author of A Brief Chapter in My Impossible Life, Harmless and How to Build a House. Her most recent novel, The Things a Brother Knows, was named a best book of the year by Kirkus, School Library Journal, Booklist and NPR. She has a new book coming out May 27 called WE ARE THE GOLDENS from Random House. (Reprinted with permission)