RALEIGH, NC (Reuters) - Americans have been reminded again and again that this is an election like none other. But with Joe Biden and President Donald Trump poised to square off at Tuesday's first 2020 presidential debate, one thing is familiar: the candidates' reliance on lawyers as debate coaches.

The president, while declaring he's only spent "a little time" readying himself to debate Biden, told reporters at the White House Sunday that former New Jersey Gov. Chris Christie and former New York City mayor Rudy Giuliani had been helping him prepare - with "a combination" of the two ex-prosecutors standing in for his Democratic opponent.

Biden, meanwhile, has been widely reported to be relying on his former vice presidential chief of staff, Ron Klain, an ex-O'Melveny & Myers partner who chaired the firm's national practice group before leaving the firm 15 years ago.

Klain was an associate White House counsel under President Bill Clinton and also served as chief of staff for Attorney General Janet Reno and Vice President Al Gore - whose recount efforts he helped command after the 2000 election. He was tapped as President Obama's Ebola Response Coordinator for two years starting in 2014.

Mainly, since leaving O'Melveny he's been working with Revolution LLC, a venture capital firm founded by AOL co-founder Steve Case. Klain is currently the company's general counsel.

Biden isn't Klain's first debate student. He was also a top debate advisor to Presidents Obama and Clinton, as well as for Gore, John Kerry and Hillary Clinton, according to his Revolution bio.

Meanwhile, another former Hillary Clinton debate coach , veteran Washington, D.C. litigator Karen Dunn, is reprising that role for Democratic vice-presidential nominee Kamala Harris, according to Bloomberg News. Senator Harris is set to debate Vice President Mike Pence on Oct. 7 in Salt Lake City.

Dunn joined Paul, Weiss, Rifkind, Wharton & Garrison in June from Boies Schiller Flexner - among the most notable in a string of Boies Schiller partner departures this year. While at her former firm, Dunn helped both Clinton and Obama prepare for candidate debates.

President Trump and Biden will debate on Tuesday in Cleveland at 9 p.m. Eastern Standard Time.