MERCY -- "Of Course I'm Not" Episode 118 -- Pictured: (l-r) Nancy Rodriquez as Mrs. Maldonado, David Anzuelo as Roberto, Diego Klattenhoff as Mike Callahan -- Photo by: Virginia Sherwood/NBC

Diego Klattenhoff, who plays betrayed husband Mike Callahan on Mercy, won’t give up too much information about tonight’s special St. Patrick’s Day episode, but rest assured, it’s going to include heavy drinking.

It’s only fitting considering the holiday is meant for stuffing your face and downing a pitcher or two, but Klattenhoff tells us that for the character of Nurse Veronica Flanagan Callahan (Taylor Schilling), it could prove risky.

Klattenhoff is starting to feel the love increasing for Mercy ever since it was rush onto the NBC schedule in the fall and now he believes the show and the actors are starting to hit their stride.

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Details on tonight’s episode.

How the show has changed.

Mercy airs Wednesday nights, 8:00 p.m. ET/PT on NBC.