Despite good reviews, Stewart was still a minor star and MGM remained hesitant to cast him in leading roles, preferring to loan him out to other studios. After a well-received supporting part in "Of Human Hearts" (1938), he was loaned to RKO to act opposite Ginger Rogers in the romantic comedy "Vivacious Lady" (1938). The production was shut down for months in 1937 as Stewart recovered from an undisclosed illness, during which he was hospitalized. RKO initially wanted to replace Stewart, but eventually, the project was canceled. However, Rogers's success in a stage musical caused the film to be picked up again. Stewart was recast in "Vivacious Lady" at Rogers's insistence and due to his performance in "Of Human Hearts". It was a critical and commercial success, and showed Stewart's talent for performing in romantic comedies; "The New York Herald" called him "one of the most knowing and engaging young actors appearing on the screen at present."