Mariah Carey spends £28,000-a year-grooming her pet dogs.

The '#Beautiful' hitmaker - who is worth around £290 million - regularly pampers her eight pet pooches by booking them into canine salons and gets them the best animal treatments so they look their best and are happy.

A source told the Daily Mirror newspaper: ''Mariah pays for all the spa therapies herself and doesn't expect any special treatment. Only her dogs get that.

''While prices start at £40 for a simple trim, other treatments are extra and Mariah's dogs really seem to enjoy their wraps and full body massages.

''She pays for her doggies to travel with her first class on a whim. And when they can't she will check them into doggy day care at salons Chateau Marmutt, Barkingham Palace or Pour La Pooch. She also employs a designated chauffeur to ferry them to and from at around £400 a time.''

Mariah's favourite treatment to get for her mutts is the popular blueberry facial, which originates in Los Angeles, and is supposed to exfoliate and reduce fur stains.

The source explained: ''She will always get the animals groomed before travelling - she likes them smart at all times.

''As well having them bathed and blow dried, Mariah is also very keen on the latest LA trend for canines - blueberry facials.''

Mariah - who has two-year-old twins, Moroccan and Monroe, with her husband Nick Cannon - is said to be ''obsessed'' with the way her dogs smell following their treatments and is delighted they help reduce wrinkles.

The source added: ''She's obsessed with how they smell after one.

''The facials are also great for getting rid of doggy wrinkles, so everyone's a winner.''