Osbourne, 62, teamed up with the property tycoon when he fronted hit US reality TV competition show "Celebrity Apprentice", and she admits she found Trump to be an "absolute gentleman".
Appearing on US late night show "Conan", she explained, "Working with him... He was very respectful, very nice, but... When you watch him on the (political) debates, it just reminds me of a three-hour episode of The Apprentice. (He's) acting the same way (as he does on the show) - the wisecracks, the one-liners... It's like, 'You're not meant to act that way. It's serious. Come on!'
Trump has captured the imaginations and support of many Americans and he is currently leading the race to be named the Republican Party's candidate for President when the nation goes to the polls next year.