Martin Pragt

From Muppet Wiki

Martin Pragt performed Tommie in Sesamstraat, the Dutch co-production of Sesame Street, during the third season in 1978.

Every now and then, Pragt and Bert Plagman (who became Tommie's steady performer in 1979) shared the part in one episode: their Tommie voices sounded almost alike. Martin left after the third season.