The Duke and Duchess of Cambridge have thrilled thousands of tiny fans in steamy Singapore, telling them they would choose invisibility if they had superpowers.

The unrelenting heat failed to deter the crowds, who gathered to cheer on the royal couple at Gardens by the Bay as they drove past in a buggy.

"Will, you're brill, Kate, you're great," chanted one group of expat kids.

Kate wore a broderie anglaise outfit designed by Alexander McQueen.

She joined William outside of the buggy to shake hands with masses of near-delirious kids. "I love her, just love her," said one young fan.

Another asked the future king what power he would pick if he was a superhero, to which William replied: "Invisibility." Kate also picked invisibility, claiming she would need it so her husband could not sneak up on her.

They were there to visit a Rolls-Royce factory. Their itinerary also takes in Malaysia, the Solomon Islands and Tuvalu.

- AAP

By Tara Ravens