MADISON, Wis. — Gov. Scott Walker’s son is joining the Senate campaign of Republican state Sen. Leah Vukmir.

Vukmir’s campaign confirmed Tuesday that Alex Walker will be working as deputy political director. Vukmir and former U.S. Marine Kevin Nicholson are the two announced Republican candidates for U.S. Senate and have been fighting over securing support from key Republican donors and others.

The governor has not endorsed anyone in the race and typically does not get publicly involved in primaries. But his son’s addition to Vukmir’s campaign is the latest in a line of those close to Walker who have joined her side.

Last week a super PAC backing Vukmir launched that’s led by Walker’s former campaign manager.

Alex Walker graduated last year from the University of Wisconsin-Madison and had been chairman of the college Republicans in Wisconsin.