Republican Presidential Candidates Share Their Pre-Debate Rituals Watch the GOP debate live on ABC Saturday at 8 p.m. ET.

As Donald Trump, Sen. Ted Cruz, Sen. Marco Rubio, Ben Carson, former Gov. Jeb Bush, Gov. Chris Christie and Gov. John Kasich gear up for tonight's GOP debate in Manchester, New Hampshire, the presidential hopefuls revealed some of their pre-debate rituals.

Cruz said he plays "Plants vs. Zombies" on his iPhone with his two daughters while Rubio asked Siri for help -- wondering what questions ABC News' David Muir may ask him.

Bush said he calls his mother, Barbara Bush, for advice.

The debate will be moderated by "World News Tonight" anchor David Muir and Chief Global Affairs Correspondent and co-anchor of "This Week with George Stephanopoulos" Martha Raddatz. Coverage begins at 8 p.m. ET on ABC.

ABC News will be hosting the debate with the Independent Journal Review, and in partnership with the Republican National Committee. Additional questions will come from WMUR political director Josh McElveen and conservative journalist Mary Katharine Ham.