EXCLUSIVE: ABC’s David Muir Interviews Scott Walker Ahead of Expected Presidential Announcement

The Wisconsin governor will become the 15th Republican to enter the race.

— -- Wisconsin Gov. Scott Walker will sit down for an exclusive interview with ABC's David Muir, anchor of “World News Tonight with David Muir,” just one day before he is expected to announce his presidential campaign.

Portions of the interview will air Monday on “Good Morning America,” "World News Tonight," “Nightline,” and ABCNews.com. Muir will also sit down with Walker’s wife, Tonette, and their two sons, Matt, 21, and Alex, 19.

Walker, 47, first gained national notoriety in 2011, when he took steps to dramatically limit the collective bargaining powers of most of the state’s public unions, including teachers. After successfully passing his controversial agenda, Walker’s opponents gathered enough signatures to organize a recall election against the governor.

Walker went on to win the 2012 recall election by a wider bargain than he won in 2010, becoming the first governor in U.S. history to overcome a recall election.

He will return to the same place where he declared victory in the 2012 recall election, the Waukesha County Expo Center, for an announcement event at 6 p.m. Monday.

Walker’s expected entry into the presidential race will make him the 15th GOP candidate to launch a White House bid.