Pastor Rick Warren canceled a Sunday morning interview with ABC News because of exhaustion, according to "This Week" host George Stephanopoulos.

Warren dropped out of the show after comments came to light that seemed to contradict the megachurch pastor's stated neutrality on Proposition 8, the California measure that banned same-sex marriage.

Warren said he had never endorsed the proposition, which passed by a narrow margin in November, during an interview last week on CNN. But a video of Warren offering an endorsement later hit YouTube, embarrassing Warren and his allies.

Gay rights activists expressed outrage when Warren was asked to give the invocation at President Obama's inauguration. The best-selling author of "The Purpose-Driven Life" has been outspoken in his opposition to abortion and gay marriage, stands that liberal activists thought should disqualify him from participating in the inauguration.