(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.