Boyd Gaines and Margaret Colin have signed on to join John Lithgow in the upcoming Broadway bow of David Auburn’s latest, “The Columnist.”

Colin (“Arcadia”) will play the wife of Joseph Alsop, the titular journo played by Lithgow. Four-time Tony winner Gaines is onboard as Stewart, Joseph’s brother and a fellow journalist.

New play by “Proof” scribe Auburn is based on the late Joseph Alsop, who was a powerful figure in the Washington politico circuit. Storyline centers on the intersection of the scribe’s career and personal life.

“Columnist” has its world preem on Broadway this spring in a production from Manhattan Theater Club, the Gotham nonprofit where “Proof” originated before producers picked it up for a commercial Rialto transfer that ran for more than two years.

“Proof” helmer Daniel Sullivan directs “Columnist.” Further casting remains to be locked in for the show, which begins previews April 4 ahead of an April 25 opening at MTC’s Samuel J. Friedman Theater.