Singer Celine Dion recently revealed that she hid her devastating battle with stiff person syndrome from her fans for 17 years, RadarOnline.com can report. In a surprising development to come more than two years after Dion, 56, announced that she was diagnosed with stiff person syndrome in December 2022, the My Heart Will Go On singer revealed that she first learned of the startling neurological disorder nearly two decades ago. Dion shared the sudden revelation during a sit-down interview with Today host Hoda Kotb ahead of the interview’s premiere on Tuesday. According to the beloved Think Twi…