The O’Neill Playwrights Conference has set the lineup of actors and directors that will join the program’s annual round of developmental readings this summer, with legit vets including Kristine Nielson, Michael Countryman and Laura Heisler, among others, on board.

Nielson and Heisler, as well as Jeremy Webb, are on tap to star in the latest from Theresa Rebeck, “Fool.” Show will be helmed by Wendy C. Goldberg, the a.d. of the conference.

Other actors set to appear in the summer slate include Zabryna Guevara (in Anne Garcia-Romero’s “Provenance”), Keira Keeley (“Provenance” and Laura Jacqmin’s “Two Lakes, Two Rivers”) and Myra Lucretia Taylor (also in “Two Lakes,” in which Countryman is cast as well).

Additional directors on the list include Lisa Peterson (Ken Weitzman’s “Reclamation”), Henry Wishcamper (“Two Lakes”), Suzanne Agins (“Alligator” by Hilary Bettis) and Hayley Finn (Meg Miroshnik’s “The Tall Girls”).

O’Neill’s NPC has had a strong track record in recent years of seeding shows that go on to have future life, with upcoming outings including Quiara Alegria Hudes’ “The Happiest Song Plays Last” at the Goodman Theater and Jennifer Haley’s “The Nether” at Center Theater Group among the titles from last year’s conference to get world premiere productions in the coming season.

The conference runs July 4-28 at the O’Neill campus in Waterford, Conn.