A member of the Mormon Tabernacle Choir has quit the esteemed singing company over its scheduled performance at President-elect Donald Trump’s inauguration in Washington DC in January.

In a resignation letter sent to fellow choir members and later posted on Facebook, singer Jan Chamberlin said she’d spent “several sleepless nights and days in turmoil and agony” since the choir announced it would perform at the inauguration, and that she could not “in good conscience” join her colleagues at the event.

“I have highly valued the mission of the Choir to be good- will ambassadors for Christ, to share beautiful music and to give hope, inspiration, and comfort to others,” Chamberlin wrote. “I’ve tried to tell myself that it will be alright and that I can continue in good conscience before God and man.”

“But it’s no use,” she added. “I simply cannot continue with the recent turn of events. I could never look myself in the mirror again with self respect.”

The Mormon Tabernacle Choir — dubbed “America’s Choir” by President Ronald Reagan at his inauguration in 1981 — has performed at the inaugurations of numerous presidents throughout history, including those for Lyndon B. Johnson, Reagan, George Bush and George W. Bush.

But since the announcement that it would perform at Trump’s inauguration, the choir has been the subject of a petition seeking to persuade the group to cancel its performance that has since gathered thousands of signatures.

“As members and friends of The Church of Jesus Christ of Latter-day Saints, we strongly urge the Church to stop this practice and especially for an incoming president who has demonstrated sexist, racist, misogynistic, and xenophobic behavior that does not align with the principles and teachings of The Church of Jesus Christ of Latter-day Saints,” the petition, which has garnered more than 23,000 signatures, states.

In her resignation letter, Chamberlin wrote that by preforming for Trump’s inauguration, it would appear to those outside the choir that the group is “endorsing tyranny and fascism.”

“And Choir’s wonderful image and networking will be severely damaged and that many good people throughout this land and throughout the world already do and will continue to feel betrayed,” she wrote. “I believe hereafter our message will not be believed by many that have loved us and adored what we have stood for.”

The Mormon Tabernacle Choir will join the Radio City Rockettes at the inauguration, while teenage opera singer Jackie Evancho is slated to perform the National Anthem.

Follow Daniel Nussbaum on Twitter: @dznussbaum