The revelation came Wednesday while the royal couple was touring Singapore. The Duke and Duchess of Cambridge are on a nine-day tour of the Far East and South Pacific in celebration of Queen Elizabeth II's Diamond Jubilee.
"Someone asked him how many children he would like to have, and he said he was thinking about having two," student Corine Ackermann said, according to Britain's Press Association.
The royal couple also visited a Rolls Royce jet engine factory in Singapore, touring the complex and unveiling the first engine produced by the plant, which opened earlier this year.
It was the couple's second day in Singapore, the first stop on their tour. They'll also visit the Solomon Islands and Tuvalu.