The actor made the announcement June 5 via Twitter. The June 6 free fan appreciation performance, the second of such events offered by The Book of Mormon, will be mark Gad's final turn as Elder Cunningham.
The actor tweeted: "Well folks, I can finally set the record straight. Tomorrow afternoon's fan performance will indeed be my last."
Representatives for the production declined to comment. Gad's replacement has not been announced. Jared Gertner, who has appeared during Gad's previous commitments, is the understudy for the role of Elder Cunningham.
Gad's upcoming projects include the NBC mid-season series "1600 Penn," about a dysfunctional White House family.
The principal cast of The Book of Mormon also features Tony nominee Andrew Rannells as Elder Price, Rory O'Malley (The 25th Annual Putnam County Spelling Bee) as Elder McKinley, Tony winner James (All Shook Up) as Nabulungi and Michael Potts (Grey Gardens) as Mafala Hatimbi, as well as Lewis Cleale, Scott Barnhardt, Justin Bohon, Darlesia Cearcy, Kevin Duda, Asmeret Ghebremichael, Brian Tyree Henry, Clark Johnsen, John Eric Parker, Jason Michael Snow, Benjamin Schrader, Michael James Scott, Brian Sears, Lawrence Stallings, Maia Nkenge Wilson, Tommar Wilson, Graham Bowen, Tyson Jennette and Nick Spangler.
"South Park" creators-writers Trey Parker and Matt Stone, and Tony-winning Avenue Q songwriter Robert Lopez collaborated on the script and score to the musical, which earned Tony Awards for Best Book, Best Score and Best Musical.