A labradoodle is a cross between a labrador and poodle
Cross-breed dogs appear to have become designer accessories for some stars, sparking a trend in the UK and US.
Popular dogs include the puggle - half pug, half beagle - and cockerpoo - a combined cocker spaniel and poodle. Some puggles are sold for up to £3,000.
The trend is said to have been fuelled by celebrities such as Ozzy Osbourne, Uma Thurman and Sylvester Stallone.
The Kennel Club said it would monitor the trend, adding: "A dog should be for life, not just for fashion."
Cross-breeders are said to be cashing in on the popularity of the peculiar pets.
Some puggle puppies reportedly change hands for up to £3,000 each, while some cockerpoos have been sold for £600.
Labradoodles, the result of the mating of a labrador and a poodle, are also proving popular.
Kennel Club spokesman Phil Buckley said the puggle was particularly popular in the US, where there are waiting lists for the cross-breed, while the labradoodle and cockerpoo were gaining in popularity in this country.
Although there are no official sales figures, the spokesman said anecdotal evidence suggested demand is growing for designer dogs.
He said there were fears that "unscrupulous breeders" would take advantage of the popularity of certain dogs by selling them at massively inflated prices and failing to provide adequate after-sale care.
Mr Buckley, who admitted that the puggle "looks delightful", told BBC News: "The average life of a dog is 12 years and it will cost around £1,000-a-year to pay for food, bedding and vet fees.
"Getting a dog is not a decision that should be taken lightly. A dog should be for life, not just for fashion."
Actor Sylvester Stallone is said to own a puggle and singer Jessica Simpson owns a Maltipoo - a Maltese and poodle cross.