SPRINGFIELD, Ill. (AP) — A gay TV star campaigned for legalizing same-sex marriage in Illinois and more than 1,000 leaders of various religious faiths signed a letter opposing it as the debate intensified over a proposal that could get its first test before a Senate committee Wednesday night.

During an appearance Wednesday in Chicago, Jesse Tyler Ferguson of the Emmy-winning series 'Modern Family' announced his support for making Illinois the 10th state to legalize gay marriage, an idea riding momentum from several events including public encouragement from President Barack Obama.

But a day after influential Cardinal Francis George of Chicago denounced the idea as going against the 'natural order' of traditional marriage, a letter from 1,700 state religious leaders was sent to every Illinois lawmaker deriding claims that the proposal wouldn't interfere with religious freedom.

'The real peril: If marriage is redefined in civil law, individuals and religious organizations — regardless of deeply held beliefs — will be compelled to treat same-sex unions as the equivalent of marriage in their lives, ministries and operations,' said the letter, penned by leaders of Catholic, Lutheran, Baptist, Mormon, Anglican, and Islamic faiths.

Sen. Heather Steans, a Chicago Democrat, told The Associated Press Monday she has enough votes to move the measure, which would remove from state law a prohibition on marriage between two people of the same sex, but didn't know when she would call it. She did not immediately return a phone call Wednesday.

She and Rep. Greg Harris, D-Chicago, the House sponsor, say their legislation would not affect any religious beliefs and religious organizations would not have to recognize or consecrate gay marriage.

Ferguson, a gay man who portrays a gay parent on the ABC comedy, said he would begin a 'Bow Tie Lobby Day' — symbolizing tying the knot — Thursday in Springfield.

'I'm looking forward to raising a family ... and having our kids grow up in an equal America,' Ferguson said at a news conference with his fiance and Lt. Gov. Sheila Simon.

Ferguson said Obama's stance in favor of 'marriage equality' has 'moved me to take more action.'