Real estate mogul and television reality star Donald Trump on Tuesday entered the crowded Republican field of candidates vying for the White House.

“So, ladies and gentlemen, I am officially running for president of the United States, and we are gong to make our country great again,” Trump told a crowd gathered at Trump Tower on Fifth Avenue in New York City.

“Our country needs a truly great leader, and we need a truly great leader now,” Trump said.

Trump also went after President Barack Obama, saying that rather than being a cheerleader for the United States, he has been “a negative force” and called the president's signature health care law “a lie.”

“We have been sold a big lie: Obamacare,” he said.

Trump, who becomes the GOP's 12th announced presidential candidate, has previously flirted with the idea of running for president.

As he contemplated a 2012 run, Trump reiterated his opposition to gay and lesbian couples marrying with a golf analogy.

“It's like in golf,” Trump told The New York Times. “A lot of people – I don’t want this to sound trivial – but a lot of people are switching to these really long putters, very unattractive. It's weird. You see these great players with these really long putters, because they can't sink three-footers anymore. And, I hate it. I am a traditionalist. I have so many fabulous friends who happen to be gay, but I am a traditionalist.”