‘Adolescence’ Co-Creator Jack Thorne, ‘Bridgerton’ Star India Amarteifio, Judi Dench Join National Youth Theatre’s 70th Anniversary Show (EXCLUSIVE)

The U.K.’s National Youth Theatre has unveiled the first wave of stars joining “Letters to My Younger Future Self,” a one-night performance marking the organization’s 70th anniversary. The show is set for Sept. 20 at Southbank Centre’s Royal Festival Hall in London and is supported by Netflix. The lineup for the evening includes BAFTA winner…