Is it permissible for a Muslim to praise another God as a courtesy during a Christian wedding?

I know some Muslims who have been invited to one of their evangelical Christian friend's weddings, and there will surely be a lot of singing and worshipping of Jesus Christ as lord and savior. Is it acceptable for a Muslim to attend such a wedding ceremony, and is it acceptable to sing songs that go against the teachings of Islam as a courtesy to Christian friends (or, for that matter, friends of other religions)?