WATCH: UFO spotted in SpaceX 'Starman' video live feed above Earth

It was only visible for a few seconds, but a number a of alien hunters watching the SpaceX launch this week spotted something unexpected dart across their view high above the Earth.

Millions had turned in to watch tech billionaire Elon Musk's launch of a Tesla roadster into space in a Falcon Heavy rocket.

The launch flung the convertible carrying a space-suited mannequin dubbed "Starman" into space on journey to Mars and beyond.

It was heralded as a "game changer" by Musk himself and watched the world over.

he SpaceX Falcon Heavy launches from Pad 39A at the Kennedy Space Center in Florida. Source: Getty
The Tesla roadster launched from the Falcon Heavy rocket with a dummy driver named 'Starman' heads towards Mars. Source: Getty

But it was a little speck seen shooting across screens as the roadster travelled into outer space that left many star gazers agape.

In the video stream beamed to Earth from the floating car, a tiny black dot sped over the globe.

A UFO seen darting across the sky between the roadster and Earth.

"My thought was a trans atmospheric skip vehicle, but I could just be hopeful," one YouTube user wrote of the Unidentified Flying Object.

"Is that aliens!!! What is this?" asked another viewer.

Other viewers were more sceptical, about the UFO, suggesting the mystery object could have been a piece of space junk or possibly a satellite.

'Don't Panic': The UFO was probably some space junk or a satellite. Source: Getty

"It might even have just been another satellite in orbit. With all the crap that's up there, it's far more likely that it's debris or something that's been in orbit for a while than it was something secret," one suggested.

"Tbh with every launch or space station video there's always a UFO sighting on the video."