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Then, on Feb. 1, his adopted daughter, McKnight, was tested and they were a match.
"I never thought I would be a match because I was adopted," McKnight told "Good Morning America." "I got the call at work and I wanted him to be the first person that knew. I called and I said, 'Daddy, I have to tell you something. I'm a match.'"
The father and daughter hope to undergo surgery shortly, GMA reported.