(CNN)Bill Clinton says he might move back to the White House — but this time, because of Hillary.
He appeared on David Letterman's CBS' "Late Show with David Letterman" that aired Tuesday night and talked about the work he's been doing with The Clinton Foundation, until Letterman asked, "Put it in a percentage, what's the chance of you moving back to 1600 Pennsylvania?"
The crowd clapped as Bill Clinton paused to respond, with a smile.
"First of all, Hillary has to win the nomination. If she wins the nomination, then she has to win the election," Clinton said. "If she wins the election, the chances are 100 percent I move back ... If I'm asked."
"I hope I will be invited. It will be a good thing for America if she won. I hope she does."
Bill Clinton has been making public appearances the last three months. Last week, he was interviewed by CNN's Christiane Amanpour, where he talked mass incarcerations and controversial donations to his foundation.
"We have been so fortunate. It's funny how perspective changes — I think having a grandchild made a big difference," Clinton told Letterman on his show.
"I urge (Hillary Clinton) to go out there and have a good time, tell the American people what you wanted to do, explain what the challenges are from her point of view and what we should do, and just be grateful. We've had a wonderful life. And I'm grateful."
Letterman asked Clinton about his granddaughter, 7-month-old Charlotte.
"She is amazing now and if you met my granddaughter, first thing she would do is take your glasses off," Clinton said while taking his glasses out of his pocket. "Her hands are working."
Letterman asked Clinton what he thinks it will be like when Charlotte finds out that her grandfather was a former president of the United States.
"Everything will turn upside down for her," Letterman said.
"By the time she gets old enough to know ... I'll have a more important role, I'll just be her grandfather," Clinton responded.
Photos: Who's running for president?
Ted Cruz, Donald Trump, John Kasich, Hillary Clinton and Bernie Sanders,
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Photos: Who's running for president?
Businessman Donald Trump announced June 16 at his Trump Tower in New York City that he is seeking the Republican presidential nomination. This ends more than two decades of flirting with the idea of running for the White House.
"So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again," Trump told the crowd at his announcement.
"So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again," Trump told the crowd at his announcement.
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Photos: Who's running for president?
Sen. Ted Cruz of Texas has made a name for himself in the Senate, solidifying his brand as a conservative firebrand willing to take on the GOP's establishment. He announced he was seeking the Republican presidential nomination in a speech on March 23.
"These are all of our stories," Cruz told the audience at Liberty University in Virginia. "These are who we are as Americans. And yet for so many Americans, the promise of America seems more and more distant."
"These are all of our stories," Cruz told the audience at Liberty University in Virginia. "These are who we are as Americans. And yet for so many Americans, the promise of America seems more and more distant."
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Photos: Who's running for president?
Ohio Gov. John Kasich joined the Republican field July 21 as he formally announced his White House bid.
"I am here to ask you for your prayers, for your support ... because I have decided to run for president of the United States," Kasich told his kickoff rally at the Ohio State University.
"I am here to ask you for your prayers, for your support ... because I have decided to run for president of the United States," Kasich told his kickoff rally at the Ohio State University.
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Photos: Who's running for president?
Hillary Clinton launched her presidential bid on April 12 through a video message on social media. The former first lady, senator and secretary of state is considered the front-runner among possible Democratic candidates.
"Everyday Americans need a champion, and I want to be that champion -- so you can do more than just get by -- you can get ahead. And stay ahead," she said in her announcement video. "Because when families are strong, America is strong. So I'm hitting the road to earn your vote, because it's your time. And I hope you'll join me on this journey."
"Everyday Americans need a champion, and I want to be that champion -- so you can do more than just get by -- you can get ahead. And stay ahead," she said in her announcement video. "Because when families are strong, America is strong. So I'm hitting the road to earn your vote, because it's your time. And I hope you'll join me on this journey."
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Photos: Who's running for president?
Sen. Bernie Sanders, an independent from Vermont who caucuses with Democrats, announced his run in an email to supporters on April 30. He has said the United States needs a "political revolution" of working-class Americans to take back control of the government from billionaires.
"This great nation and its government belong to all of the people and not to a handful of billionaires, their super PACs and their lobbyists," Sanders said at a rally in Vermont on May 26.
"This great nation and its government belong to all of the people and not to a handful of billionaires, their super PACs and their lobbyists," Sanders said at a rally in Vermont on May 26.
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