A cat from Hampshire and a dog from Yorkshire that together managed to shed 33kg (73lb) were named joint winners of the 2005 Slimmer of the Year contest.
Benji used to be 10.80kg but has now lost 30% of his body weight
Benji, a seven-year-old ginger moggy from Fareham lost 30% of his body weight and now weighs 7.55kg (17lb).
Five-year-old Scrappy, a labrador from Hebden Bridge, shed nearly 30kg (66lb) - 45% of his body weight.
The animals bagged £2,500 worth of holiday vouchers and pet accessories as well as a year's free supply of food.
Scrappy went from a whopping 65.45kg (144lb) to 36kg (79lb) and his owners, David and Pat Grant, said they were pleased as it meant his health had improved and he would be expected to live longer.
Scrappy used to be 65.45kg but has shed nearly half of his body weight
Mr Grant said: "I'm extremely proud of Scrappy. When he was overweight he was so lethargic and couldn't even manage to go for a walk.
"Now he's fit and active and seems years younger."
Both pets will now go into the Hill's European Pet Slimmer of the Year Awards, to compete against national champions from France, Spain, Italy, Germany and Switzerland.