By Kelly-Ann Mills for Mirror

This cute little four-year-old received two of the same toy for his birthday, so went with his dad to exchange one for something else.

As this heartwarming video shows it wasn't an Action Man or a Caped Crusader that caught young Isaiah Willis' eye, but a Little Mermaid Barbie doll.

But what has caused this clip to go viral was his remarkable dad Mikki's reaction to his choice.

In the recording, uploaded to Facebook, Mikki looks seriously into the camera and asks: "How do you think a dad feels when his son wants to get THIS..."

But before anyone has chance to question it, young Isaiah simply shouts: "YEAAAAAH".

And his enthusiastic dad repeats the young boy's excitement.

But the most touching part of the video is the dad talking to his son.

He says: "I let my boys choose their life, that’s how momma and I are, we just say whatever. We say yeah."

"Choose it, choose your expression, choose what you’re into, choose your sexuality, choose whatever," he continued.

"You have my promise forever to love you and accept you, no matter what life you choose."

A comment that received another squeal of excitement from his eldest boy.

The accepting dad's clip has racked up more than 8.7 million views since it was uploaded on Friday.