Moving `` Tonight '' -- which has held its current slot for decades -- back a half-hour is likely to hurt the show , and Berman predicted that NBC will be unable to keep all three hosts . NEW : Mediaweek analyst , at least one among Leno , O'Brien and Fallon will leave . NBC : Leno to host half - hour show starting at 11:35 p.m . ET ; Fallon moving to 12:05 ; Fallon 's 10 p.m. show to go off the air next month when Winter Olympics start . TV host moved to 10 p.m. slot in September ; ratings have been low .
NEW : Mediaweek analyst , at least one among Leno , O'Brien and Fallon will leave . NBC : Leno to host half - hour show starting at 11:35 p.m . ET ; Fallon moving to 12:05 ; Fallon 's 10 p.m. show to go off the air next month when Winter Olympics start . TV host moved to 10 p.m. slot in September ; ratings have been low .