The 'Stronger' singer suffered the injury while performing at the Milwaukee Summerfest over the weekend, according to WENN.
Clarkson's ailment has forced her to use a wheelchair, but the injury did not stop her from making several promotional appearances on Tuesday (July 3).
"Sprained my foot and have a hairline fracture but the show must go on people ha," she tweeted.
Clarkson is to launch her summer tour on July 21 in Ridgefield, WA at the Sleep Country Amphitheater. The event is expected to go on as scheduled.
She also appears as a mentor on Duets, which airs Thursdays at 8/7c on ABC.
Watch Kelly Clarkson's 'Stronger (What Doesn't Kill You)' music video below: