Pittsburgh Mayor Bill Peduto will hold a wedding ceremony for 20 gay and lesbian couples on Sunday morning.

Pennsylvania became the 19th state, in addition to the District of Columbia, to allow gay couples to marry when Republican Governor Tom Corbett decided against pursuing an appeal to a ruling striking down the state's marriage ban as invalid.

(Related : Pennsylvania Gov. Tom Corbett says he won't appeal gay marriage ruling.)

The ceremony will take place in Triangle Park Downtown during PrideFest, the city's annual Gay Pride celebration. A reception to be held at the adjacent Fairmont Hotel will take place after the ceremony. The private event will be broadcast live on the city's cable TV channel.

“I said last week I would be thrilled to make the marriage of an LGBT couple the first I officiate as mayor, and being able to share that moment with many others should make for an even more joyous celebration,” Peduto said in a written statement.