Cloud, Minnesota, Thelen made her screen debut as Georgia Miles, "a willfully free-spirited girl, naive and narcissistic"[1] in Four Friends in 1981.
Thelen appeared on Broadway in Brighton Beach Memoirs in 1983.
Her off-Broadway credits include Springtime for Henry, Largo Desolato at The Public Theater, The Nice and the Nasty at Playwrights Horizons, The Chemistry of Change, and A Body of Water, in which she played the dual roles of Sandy and Malka.
For the latter, Variety praised her "stunning transformation" between roles,[2] while The New York Times noted the "welcome comic bite" of her Malka portrayal.
[3] Thelen's television credits include Duet, Grace Under Fire, Touched by an Angel, Joan of Arcadia and Twin Peaks.