MUSTWORTHINESS He infuses Kevin, Joan's paralyzed brother on CBS' ''Joan of Arcadia,'' with soul and bravery -- traits that Ritter, who lost dad John Ritter while filming the series' fifth episode, oozes in real life. Plus, he can do funny (''Mumford'') and camp (''Freddy vs. Jason'').
WHEN HE FIRST KNEW HE WANTED TO ACT ''I was about 5 and in my little bunk bed at home.''
WHAT DAD SAID ''He never tried to talk me out of it. He was supportive of whatever we wanted to do.''
A TIGHTS SPOT ''At age 8, I played Theo in 'Pippin' [with Jack Black in the title role of the school production]. All my friends said they could see through my tights.''
WORST JOB ''Flipping chicken burgers at a Little League game. I didn't cook them all the way through. I had to buy back about 16.''
IF HE WASN'T ACTING, HE'D BE... ''Doing mime on the Third Street promenade in Santa Monica.''
HE'S HELL ON WHEELS ''I can do a one-handed wheelie [with the wheelchair] and bounce down two stairs. I ran over [costar] Mary Steenburgen's toes a billion times.''
NEXT The Don Roos feature ''Happy Endings,'' starring Maggie Gyllenhaal and Lisa Kudrow, and season 2 of ''Joan.''