ET Exclusive Vid: 'Celebrity Circus' Bombshell!

Watch our exclusive interview! In a bombshell announcement on Wednesday's episode of NBC's "Celebrity Circus," former "Brady Bunch" and "My Fair Brady" star Christopher Knight announced that he would be leaving the show due to a broken arm. He announced that he had fallen in rehearsal the day before and did more damage to his already-injured arm. "This has been an incredible journey," Christopher said on Wednesday night's show, "and I really wish that I could continue the journey with you, but the doctors shut me down." Speaking exclusively to ET about his exit, Christopher said, "I have to go start some new therapy tomorrow and re-heal it because it's now broken again, but it doesn't hurt, which is sort of troubling, you know, so I have to remember that it's broken so I don't use it."