A US version of reality TV cooking show MasterChef, with fiery chef Gordon Ramsay as one of the judges, has made an impressive debut.

MasterChef, airing on Rupert Murdoch's American free-to-air TV network FOX on Tuesday night drew almost six million viewers - making it the highest-rated premiere of the current US summer TV season.

The ratings haul continues the show's impressive performance, with Australian and British versions major hits.

Ramsay is a staple on Murdoch's FOX network, with his other reality shows, Hell's Kitchen and Ramsay's Kitchen Nightmares, popular with American viewers, but on MasterChef they see a different side of the expletive-tossing British chef.

He shows off a gentler side to the amateur contestants, rather than dishing up harsh nicknames and firing off four-letter tirades at the professionals he deals with on his other shows.

"That wouldn't be fair, you have to keep in mind that these are not professionals," Ramsay told the Los Angeles Times.