Businessman Donald TrumpDonald John TrumpConservatives express concern over House GOP immigration bill Poll: McSally holds 14-point lead in Arizona GOP Senate primary Trump defends Nielsen amid criticism over family separations MORE, who considered his own bid against President Obama, said he was honored that the president brought him up during Wednesday night's debate.

Trump's daughter Ivanka said she was also pleased to hear her father's name come up.

Obama referred to Trump while critiquing Romney's tax plan, saying Romney's proposal would shift the tax burden onto middle-class families.

"Under Gov. Romney's definition, there are a bunch of millionaires and billionaires who are small businesses," Obama said. "I know Donald Trump doesn't like to think of himself as small anything, but that's how you define small businesses if you're getting business income."

Trump is an outspoken Romney supporter who has campaigned on behalf of the GOP nominee. He has stirred controversy by repeatedly questioning whether Obama was really born in Hawaii.

The president dismissed Trump as a "carnival barker" last year when he released his long-form birth certificate to the public.