According to Gigaom, Netflix has started testing 4K videos ahead of a possible launch of Ultra HD in 2014.
The video streaming service has reportedly sneaked in seven videos all titled 'El Fuente' but differing rates of frames per second.
The videos show a collection of travel footage from Mexico but, according to the video descriptions, show an "example of 4K."
Netflix CEO Reed Hastings recently announced that Netflix wants to be "one of the big suppliers of 4K next year," and according to Netflix Chief Product officer Neil Hunt the company are hoping to offer 4K streaming options inside two year's time.
Hunt stated back in March this year, "Clearly we have much work to do with the compression and decode capability, but we expect to be delivering 4K within a year or two with at least some movies and then over time become an important source of 4K."
The 4K Ultra HD quality videos are rumoured to be for Netflix's own original content, such as House of Cards, but may also be used in content from its licensing partners.
Earlier this year it was reported that Netflix uses piracy to measure what TV shows it should buy.