AceShowbiz - Actor/rapper Brandon Mychal Smith has been forced to hang up his ice skates and quit U.S. reality show "Skating with the Stars" after falling ill with a mystery ailment. The "Sonny with a Chance" star initially pulled out of the TV competition last week after he was hospitalized with breathing difficulties.

It later emerged he had also been vomiting during rehearsals and a representative for the show attributed the sickness to food poisoning. But the 21 year old found himself back in hospital after the incident and has undergone tests to determine the cause of his illness. Sources close to Smith tell TMZ.com the actor has been left so weak by the ailment, he's barely able to stand.

Brandon Mychal Smith was supposed to continue competing on the "Dancing with the Stars" spin-off program alongside rocker Vince Neil and actress Rebecca Budig.