The Lyndsey Turner-helmed production will run at the Barbican Theatre.
Steve Solomon's one-man comedy returns to New York for a limited run.
The evening will benefit the newly created Michael Morones Foundation.
Spector plays a young version of Mann in the Broadway hit Beautiful — The Carole King Musical.
Tough Titty, inspired by Lampley's experiences battling breast cancer, will play the Paradise Factory.
McGowan will star opposite Erin Mackey in the Rodgers and Hammerstein classic.
The York Theatre Company event will reflect on the three-time Tony-winning Broadway icon's illustrious career.
Ciarán O'Reilly will direct the Gardner McKay play.
LCT3 will open the new family drama this June.
The annual gender-bending benefit show outdid itself in its ninth year.