<Tr> <Td> </Td> <Td> </Td> <Td> 25 </Td> <Td> May 16, 2002 (2002 - 05 - 16) </Td> <Td> February 25, 2003 (2003 - 02 - 25) </Td> </Tr> <Ul> <Li> Clifford the Big Red Dog (voiced by John Ritter; Tom Eastwood in the British version): A giant red Labrador Retriever / Vizsla cross . The depiction of Clifford's size is inconsistent; he is often shown as being about 25 feet tall (7.6 m) from paws to head, but can appear far larger . The character is based on the imaginary friend of creator Norman Bridwell's wife . Clifford is devoted to his owner Emily Elizabeth . He is friendly, shy, lovable, loyal, gentle and helpful but sometimes gets into trouble because of his size, or is tempted into trouble by his friends and those he meets . Despite being the protagonist, he seldom has episodes focusing on him, usually serving as the voice - of - reason for his friend's adventures . </Li> <Li> Cleo (voiced by Cree Summer; Regine Candler in the British version): An energetic and playful, yet selfish and mischievous purple poodle with a tendency to not tell the truth . Her catchphrase is "Have I ever steered you wrong?" which she inadvertently does immediately after . She is one of Clifford's best friends . Her owner is Mrs. Diller . </Li> <Li> T - Bone (voiced by Kel Mitchell; Benjamin Small in the British version): A male yellow and orange bulldog with a large appetite . He is often cowardly, clumsy, and cautious, but does have his moments of bravery . He is one of Clifford's best friends . T - Bone is in love with Mimi, another dog who visits from time to time . His owner is Sheriff Lewis . <Ul> <Li> T - Bone had a best friend named Hamburger (voiced by Kel Mitchell's longtime comedy partner Kenan Thompson) who moved away before Clifford arrived . </Li> </Ul> </Li> <Li> Mac (voiced by Cameron Clarke): A male blue greyhound with an inflated sense of self - importance, who shifts between aloofness and wanting to be part of Clifford, Cleo, and T - Bone's circle of friends . Mac competes in dog shows . He can be vain, bossy and selfish . However, he appears to be devoted to his owner Jetta . It is revealed in a few episodes that his name is short for Machiavelli . </Li> </Ul> <Li> Clifford the Big Red Dog (voiced by John Ritter; Tom Eastwood in the British version): A giant red Labrador Retriever / Vizsla cross . The depiction of Clifford's size is inconsistent; he is often shown as being about 25 feet tall (7.6 m) from paws to head, but can appear far larger . The character is based on the imaginary friend of creator Norman Bridwell's wife . Clifford is devoted to his owner Emily Elizabeth . He is friendly, shy, lovable, loyal, gentle and helpful but sometimes gets into trouble because of his size, or is tempted into trouble by his friends and those he meets . Despite being the protagonist, he seldom has episodes focusing on him, usually serving as the voice - of - reason for his friend's adventures . </Li> <Li> Cleo (voiced by Cree Summer; Regine Candler in the British version): An energetic and playful, yet selfish and mischievous purple poodle with a tendency to not tell the truth . Her catchphrase is "Have I ever steered you wrong?" which she inadvertently does immediately after . She is one of Clifford's best friends . Her owner is Mrs. Diller . </Li>

Who does clifford the big red dog voice