Donnelly, formerly of Aston Villa’s academy, operates primarily down the right flank and was most recently with Southern Central Division side Redditch United.
He goes straight into contention ahead of Saturday’s trip to Shepshed Dynamo.
Discussing the signing, Yeltz joint-manager Craig Nicholls said: "Kieren was someone we've kept our eye on for a while.
"He has the luxury of being able to play in a number of positions and at a very high level.
"We are really excited to get Kieren in and involved in the group, and I'm sure the Yeltz faithful will see a player who gives everything for the cause."
Photo credit: Halesowen Town
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