LOS ANGELES, Sept. 9 /PRNewswire/ -- Kelly Clarkson has been diagnosed with bronchitis and, under doctor's orders, has postponed her next three tour dates. She was due to perform in Reno, Nevada on Sept. 9; Las Vegas on Sept. 10 and Spokane on Sept. 12. Earlier this week, Clarkson was forced to postpone two appearances in Southern California because of bronchitis. Performances in Santa Barbara on Sept. 5 and Irvine on Sept. 7 were called off, but Clarkson was hoping to sufficiently recover in time for the Reno, Las Vegas and Spokane shows. At a soundcheck earlier today, Clarkson was still feeling ill, and it became obvious she would not be able to perform an entire show. Clarkson's "Hazel Eyes" tour in support of her triple-platinum "Breakaway" album began June 29th in Del Mar, Calif. She has played 42 dates since the tour launched. The tour was scheduled to conclude this week. The re-scheduled tour dates are expected to take place later this year and tickets previously purchased for all performances will be honored for the rescheduled dates. Despite her bronchitis, Clarkson will perform one song on MTV's "ReAct Now: Music & Relief," a telethon to raise money for Hurricane Katrina relief. The charity special will air live on Saturday, Sept. 10 (8-11 p.m. EDT).