The debate over gay marriage in Illinois begins on Wednesday with the introduction of a bill in the Senate.

State Senator Heather Steans, a Democrat from Chicago, is expected to introduce the Religious Freedom and Marriage Fairness Act in a meeting of the Senate Executive Committee being held during a brief lame-duck session.

If the bill is approved, Steans will call for a vote on the Senate floor, possibly as early as Thursday. Steans has previously described the possibility of passage during the special session as “close.”

The House will open its lame-duck session on Sunday.

Meanwhile, Jesse Tyler Ferguson, who co-stars on ABC's Modern Family, joined Illinois Lt. Governor Sheila Simon and marriage equality advocates in Chicago to lobby for the bill.

Ferguson said Modern Family, which features a gay couple raising a daughter, has helped move the issue forward.

“I think it's a bit like a Trojan horse,” he said. “A lot of people who were not comfortable with marriage equality … turn on the television and see a show that has a lot of different families in it – and one of those families just happens to be gay. They're realizing they have a great time watching the show, then they're watching a gay couple that's having a lot of the same problems and issues they have. They realize, 'Oh they're not so different from me.' And at that point, we're in their living rooms.”

(Related: Jesse Tyler Ferguson, star of Modern Family, to lobby for Illinois gay marriage.)