Ambitious open-space exploration game 'No Man's Sky' might not be launched on June 21, according to a Kotaku source.

Kotaku reported that two reliable sources has confirmed that the highly anticipated game's release date will be pushed back to July or August this year. One source, said to be an employee of retailer Gamestop, told Kotaku that 'No Man's Sky' marketing posters were received today, with the original June 21 release date printed on the material. However, they were advised that the date on the materials were incorrect, and were advised to cover up the text with a "Coming Soon" label.

Forbes confirmed, however, that online retailers, such as Amazon, still have the original June 21 release date posted for No Man's Sky. On the online retailer iam8bit's UK pre-order page, it still says that the pre-orders will ship late June 2016.

No Man's Sky is developed by UK-based team Hello Games, the same studio behind the side-scrolling Joe Danger games. The game was first announced at Spike's VGX Awards almost three years ago, and was met with a lot of hype. Sony Entertainment has presented it at E3 in 2014 and 2015. PC Advisor reported that while No Man's Sky is an indie title, Sony has treated the game like it was created by one of the company's studios. "We have been working very closely with the developers and bringing it into our release programme as if we had made it," Sony UK's Commercial Director, Fergal Gara, said. "We are not going to treat it any differently and we are going to put the full weight of PlayStation behind it. If it all comes together as well as expected, it will be treated like a first-party release; it is not a self-published small indie title on the platform."

The space exploration game will launch on the PS4 and PC, with no word on an Xbox One release.