Question: who sings the theme song for the grinch
Answer: Thurl Arthur Ravenscroft ( / ˈθɜːrl ˈreɪvənzkrɒft / ; February 6 , 1914 -- May 22 , 2005 ) was an American voice actor and bass singer known as the booming voice behind Tony the Tiger 's `` They 're grrreat ! '' in Kellogg 's Frosted Flakes television commercials for more than five decades .