The hallowed walls of the most exclusive doghouse in the nation, the Westminster Kennel Club Dog Show, will this year be open to competitors once considered unthinkable for the elite competition: mixed breeds.

The mixed-breed competitors will only be let into the show through the doggie door, however, in a new agility trial that will precede the start of the two-day show next month.

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The club's president, Sean McCarthy, told reporters Wednesday that the competition would "make sure we show all aspects of what dogs can do; they're good-looking, skillful and talented," according to The Associated Press.

The first Masters Agility Championship at Westminster will include a field of 225 Labradoodles and the like competing through two qualifying rounds of an obstacle course of sorts, running through tires and tunnels, to make it to the televised, championship round. The competition, to be held Sat., Feb. 8, at Pier 94 in New York City, will include 16 mixed-breed dogs, The Associated Press reports.

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The two-day Westminster show, with 2,845 entrants, will take place two days later, Feb. 10-11, at Madison Square Garden.

The 138th annual show for purebred dogs is making history itself by welcoming three new breeds into the competition: the Chinook, the rat terrier and the Portuguese Podengo Pequeno.

The breeds, all newly recognized by the American Kennel Club, will make up 32 entries combined out of the total of 2,845 competitors.

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Labrador retrievers, the most-registered American Kennel Club breed every year since 1991, lead the way again with 76 entries in this year's competition, followed by golden retrievers with 58, French bulldogs with 52, Rhodesian ridgebacks with 46 and Australian shepherds with 44, according to the club's website.

Coverage of the 2014 show will be live streamed on the Westminster website and Westminster app and aired on USA Network and CNBC.