Robin Williams fans have been left speechless after watching "ROBIN," a test footage clip of actor Jamie Costa impersonating the legendary late actor on YouTube to uncanny effect.

The 5-minute scene features Costa as Williams back in 1982, when the late actor-comedian was filming his hit television series Mork & Mindy, which ran between 1978 and 1982). Actress Sarah Murphee starred as Pam Dawber alongside Williams in the show.

Costa's clip recreates the moment that Williams learned of his late friend John Belushi's death. In real life, Williams had dinner with Belushi the night before he passed away.

"No, I told you, I was with him. John's not dead, I was with him last night," Costa as Williams says in the clip, emanating Williams' raw emotionality.

The scene ends with a knock at Williams' dressing room door. He stares into the mirror as he shakes off his shock, disbelief and grief so he can return to set.

Watch below:

During the scene, Costa nails even the most subtle of Williams' mannerisms as he navigates through several emotions in the blink of an eye. What stands out the most is his sense of humanity and warmth, something that Williams was known for.

Although there is not currently a Robin Williams biopic in the works (to our public knowledge, anyway), Costa likely released the test footage to showcase his acting skills for consideration for potential future projects.

So, who exactly is Jamie Costa?

Costa is an actor, producer, director, writer, voice actor and impressionist. He first shot to fame after publishing the 2014 short film Never Had a Friend Like Him to his YouTube channel. The 2-minute montage showcased Costa in some of Williams' most notable roles.

See some of the best social media reactions to "ROBIN," below.

Not all reactions have been completely positive, though.

On Tuesday (Oct. 12), Williams' daughter Zelda responded to the video. In a tweet, she shared that fans have been sending her the video nonstop and requested that people stop tagging her in the clip on social media, as it is emotionally triggering.

She did, however, add that Costa's impression was "talented," and not the core issue.

"Guys, I’m only saying this because I don’t think it’ll stop until I acknowledge it… please, stop sending me the 'test footage.' I’ve seen it. Jamie is SUPER talented, this isn’t against him, but y’all spamming me an impression of my late Dad on one of his saddest days is weird," she wrote.

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