Music mogul Simon Cowell is reportedly apprehensive about allowing Leona Lewis to embark on a world tour - because he is unsure if the newcomer is ready to perform in front of thousands of fans.
The 'American Idol' judge has overseen the 'Bleeding Love' hitmaker's career since she won his British talent show 'The X-Factor' in 2006.
Cowell persuaded top American producers to work with Lewis on her debut album 'Spirit', including legendary music executive Clive Davis.
And it paid off - the album sold over four million copies worldwide, making the singer an instant superstar and garnering her three Grammy nominations at the forthcoming 2009 ceremony.
But Cowell is eager to leave any plans for a world tour on hiatus - until the singer has the confidence to take on arena audiences, according to Britain's 'The Sun' newspaper.
A source tells the publication: "Although Simon believes in Leona as a world-class solo singer, he still feels she does not have enough confidence to play to large crowds on her own.
"There is certainly a real art to getting the audience in the palm of your hand as entertainers as Mariah (Carey), Robbie Williams and Elton John can do.
"Leona is Simon's little baby and he is very aware of how shy she is."