Dollar Shave Club cofounder and CEO Michael Dubin. YouTube/Dollar Shave Club Razor industry leader Gillette, which is owned by Procter & Gamble, has filed a lawsuit against Dollar Shave Club that accuses the popular startup of patent infringement.

Dollar Shave Club was founded in 2011 and launched its subscription service in March 2012, offering razors at a significant discount to Gillette's, mailed direct to consumer.

In its lawsuit, Gillette claims that Dollar Shave Club is violating several sections of its "Razor Technology" patent, which is used in the design of its Mach 3, Venus, and Fusion razors.

Dollar Shave Club declined to comment on the lawsuit.

Dollar Shave Club's subscription service has grown rapidly, making the company a new competitor to industry giants. It said this fall that it had passed Schick as the No. 2 men's razor company in terms of sales, which Dollar Shave Club's cofounder and CEO Michael Dubin told the LA Times were on track to be $140 million this year. The company says it has 2.4 million subscribers, and the Wall Street Journal reports that this would mean it has 8% of the $3 billion US razor market.

Earlier this year Gillette launched its own online subscription plan for its razors apparently to compete with Dollar Shave Club and newer service Harry's. Procter & Gamble does not publicly separate Gillette out from its family of grooming businesses, but reported that its grooming businesses' third-quarter net sales this year dropped to $1.7 billion, down 14% from last year.

Since launch, bloggers and journalists have pointed out that Dollar Shave Club seems to resell Korean company Dorco's razors at a markup, and while Dollar Shave Club has never publicly acknowledged a relationship, Re/code reported that Dorco is a stakeholder in Dollar Shave Club.

Business Insider asked a Gillette representative if she was aware of a relationship with Dorco, to which she replied, "We actually don't have any confirmation on the source of their blades. To the best of our knowledge, they have not publicly disclosed or confirmed the source. Dollar Shave is the only party listed in the suit."

Dorco was not available for comment at the time of publishing.

Here's Dorco's Pace 6 Plus compared to Dollar Shave Club's The Executive:

And here's the Gillette Fusion: