Poet and songwriter Tho Olthuis (b. 1941) has written many novels especially for children, and since 1981 has written mostly for Sesamstraat and theater. Until the end of the 90's he was also a writer and lyricist for other educational children's programs. He is also famous for his lyrics for other Dutch artists such as Herman van Veen.
He is mostly known for his typical ironic kind of humor. Besides lyric writing for the music, he also composes rhymes and short stories for the show.