Facebook’s co-founder and CEO, Mark Zuckerberg, has appeared in court for the first time based on claims that Oculus, which was acquired by Facebook in 2014, had stolen Oculus Rift technology.

Owner of games studio software, ZeniMax Media, is suing Facebook for $2 billion. The company has accused Facebook of completing its acquisition of Oculus in July 2014 with full awareness that its consumer devices were inappropriate.

In court, Zuckerberg said: “I am aware of the claims; I’m here because I believe they’re false and it’s important to testify that.”

The Facebook CEO also openly revealed that the company paid $3 billion towards the acquisition of Oculus, as opposed to the previously reported $2.3 billion.

The issue first surfaced in 2012 when a ZeniMax employee began speaking to Palmer Luckey, the founder of Oculus. During this time, Luckey was working on the construction of the virtual reality headset, Rift.

ZeniMax’s lawsuit claims that it was just a somewhat ‘basic’ prototype that did not include a head mount, virtual-reality software, integrated motion sensors and other critical features and capabilities needed to create the virtual reality headset.

The company says that it was its employee, John Carmack, who transformed the Rift into the final product, a ‘powerful immersive virtual reality experience.’ This, however, did not lead to the company receiving compensation after the CEO’s disagreement with Luckey.

ZeniMax appeared in court requesting  $2 billion in damages. However, Facebook stood in disagreement objecting that no claim was made by the company to own the technology when Facebook revealed it would be acquiring Oculus in 2014.

Zuckerberg added: “We were having a lot of conversations internally on our side whether this was the right thing to go forward and do. Everyone will admit $2 billion is a lot of investment.”

The Facebook CEO also announced that he had never heard of ZeniMax before its allegation claiming: “It’s pretty common when you announce a big deal that people just come out of the woodwork and claim they own some part of the deal.”