Frontrunner for the Republican presidential nomination, Donald Trump has won the endorsement of New Jersey Governor Chris Christie, a massive coup for the Trump campaign as it heads towards Super Tuesday on 1 March.

Christie, who hoped to gain the Republican nomination himself before dropping out after the New Hampshire primary, endorsed Trump at Fort Worth, Texas following last night's Republican presidential debate in the lone star state.

"I am proud to be here to endorse Donald Trump," said Christie, noting he and the former reality TV star had been friends for the last ten years, the New York Times reported. He added that Trump "will do exactly what needs to be done to make America a leader around the world again."

"He's been my friend for many years, he's been a spectacular governor," Trump said of Christie, who lends the outspoken frontrunner some of his moderate credibility with the endorsement.

Polls have Trump ahead in the seven Super Tuesday states (Alabama, Alaska, Arkansas, Georgia, Massachusetts, Minnesota, North Dakota, Oklahoma, Tennessee, Texas, Vermont, Virginia, Wyoming).

The Hill reported that Trump has 37% support in the seven states, citing a Bloomberg poll. Marco Rubio and Ted Cruz, his closest rivals, have 20% each.

With the establishment field split, Trump will want to win as big as he can on Super Tuesday before he is faced by a stronger rival for the nomination.