You have to watch out when Keon the Irish wolfhound starts wagging his tail because it is a huge 76.8 cm (30.2 in) long.
The friendly dog has broken the previous record for the Longest tail on a dog, held by a fellow wolfhound, by just over 4.5 cm (1.7 in).
Before achieving this record, Keon was required to be examined by a professional vet, who measured the tail from the top of the bone to the tip - not including the hair.
Keon is an Irish name that means "courageous warrior", but his owner Ilse Loodts says that he is a gentle giant.
Guinness World Records recently visited Keon and his family in Westerlo, Belgium, to present the extraordinary canine with an official certificate and set up a photoshoot for the Guinness World Records 2017 Edition book.
Other impressive pooches that have made it into this year’s annual include Lizzy, the Tallest female dog, and Smurf, who holds the title Most tricks performed by a dog in one minute.
Guinness World Records 2017 Edition and Guinness World Records 2017 Gamer's Edition are in stores now.