Facebook will begin testing advertisements inside its virtual reality (VR) Oculus headsets in partnership with several game developers, it has announced.
That follows the start of ad testing in the Oculus mobile app last month.
The company says it will use the test to explore ways to help developers earn revenue on the Oculus platform and to help VR become mainstream.
"While this is an early test, we're excited by the opportunity to open up new revenue streams for developers and as a result, broaden the type of apps and content on the Oculus platform," the company said in a blog post.
"A more profitable content ecosystem is a critical step on the path to consumer VR becoming truly mainstream. And that's something we think is worth celebrating."
Ads will begin to appear in Resolution's action game Blaston among others over the coming weeks.
"Once we see how this test goes and incorporate feedback from developers and the community, we'll provide more details on when ads may become more broadly available across the Oculus platform and in the Oculus mobile app," the company said in a blog post.
Facebook also said Oculus users will be able to choose not to see ads from certain advertisers as well as hide individual ads.
The move contradicts the words of Palmer Luckey, who originally founded Oculus before selling it to Facebook in 2014 for US$3 billion and remaining with the company until 2017.
At the time the sale was announced he wrote that Oculus would operate independently.
"This deal lets us dedicate a lot of resources to developer relations, technical help, engine optimisations, and our content investment/publishing/sales platform," he wrote.
"We are not going to track you, flash ads at you, or do anything invasive."