A spiral galaxy system that spans more than 522,000 light-years has been identified by a team of astronomers.
The spectacular spiral galaxy, NGC 6872, is the biggest yet seen.
Astronomers earmarked the galaxy using archival data taken from Nasa's Galaxy Evolution Explorer (Galex) satellite.
NGC 6872 ranked among the biggest stellar systems for decades, but the new analysis has now crowned it the largest known spiral.
The discovery indicates that the galaxy is five time the size of the Milky Way galaxy.
The team of astronomers say that a comparatively recent collision with another galaxy could be causing one of the outer arms of the spiral to spawn fresh stars that may eventually create a new galaxy.
The team of astronomers from Brazil, Chile and the US were led by lead scientist Rafael Eufrasio who presented the findings on Thursday at the American Astronomical Society meeting in Long Beach, California.
"It's been known to be among the largest for two decades, but it's much larger than we thought," explained Mr Eufrasio.
"The galaxy that collided with the [central disc of NGC 6872] splashed stars all over the place - 500,000 light years away."
Mr Eufrasio told the BBC that the team had made the discovery by accident saying: "I was not looking for the largest spiral - it just came as a gift".
The Galex space telescope was designed to search for ultraviolet light that newly born stars put out, it was that feature that hinted that NGC 6872 was made much larger in size by a collision.
The two galaxies are located around 212 million light-years from Earth.