Actors Matt Damon (L) and Ben Affleck attend HBO's "Project Greenlight" Season 4 where they revealed this year's winner at Boulevard3 in the Hollywood section of Los Angeles on November 7, 2014. "Project Greenlight", which ran for three seasons before ending in 2005, is returning to HBO in spring 2015 with Matt Damon and Ben Affleck as Executive Producers. Photo by UPI/Jim Ruymen | License Photo

Mick Jagger arrives on the red carpet at the New York premiere of HBO's "Vinyl" in New York City on January 15, 2016. On August 16, several of HBO's Twitter accounts were hacked for approximately 40 minutes. File Photo by John Angelillo/UPI | License Photo

Aug. 17 (UPI) -- HBO was once again a hacking victim after its Twitter account was compromised Wednesday night.

The hack lasted for about 40 mnutes until HBO was finally bale to regain control of its account and delete the tweets. During that time, the hacker wrote "OurMine are here, we are just testing your security."


The hacker then urged HBO to visit its website to "upgrade the security."

OurMine also hacked the Twitter accounts for HBO shows, including Game of Thrones and Girls.

HBO told NBC News that "we are investigating."

Days earlier, hackers got access to several unaired episodes of Curb Your Enthusiasm and released them online.

Although it's not yet certain if OurMine hacked the HBO Twitter accounts, hackers identifying themselves have been involved in several high-profile social media attacks, including Google CEO Sundar Pichai, Facebook CEO Mark Zuckerberg, Wikipedia co-founder Jimmy Wales, BuzzFeed and TechCrunch, reported the New York Times.

The hacking of HBO's social media came on the same day the channel accidentally uploaded the next episode of Game of Thrones to its on-demand service in Spain for one hour before it was removed. By that time, however, the episode was already uploaded to various sources online.