updated 06/15/2012 AT 9:00 PM ET
•originally published 06/17/2012 AT 7:00 PM ET
Jack Osbourne has been diagnosed with multiple sclerosis, he tells PEOPLE exclusively.
Just two weeks after he and fiancée Lisa Stelly welcomed daughter Pearl Clementine, Osbourne, 26, was dealt the shocking news. In an exclusive, sit-down interview and photo shoot with PEOPLE magazine, Jack and his mother Sharon open up about their emotional ordeal.
“I was just angry and frustrated and kept thinking, ‘Why now?’ ” Jack tells PEOPLE. “I’ve got a family and that’s what’s supposed to be the most important thing.”
Multiple sclerosis is a disease that affects the central nervous system – the brain and spinal cord – and can cause problems with muscle control and strength, vision, balance, feeling, and thinking.