First lady Michelle Obama said she has not watched any of the 2012 Republican National Convention; aides to her husband, President Obama, said he hasn't either.

But Michelle Obama told "Late Show" host David Letterman tonight that "it's very important for everyone to watch as much of both conventions as possible" - reflecting a confidence among Democrats that voters who take a close look at the Republican ticket won't like what they see.

"Let me start by saying I, as the wife of the guy they're running against, I tend not to watch it, but I think it's important for everyone to watch these conventions because this is the time you get to know the party, you understand the platform, you understand the candidates," Obama said, according to advance excerpts of her appearance released by the show.

Her late night appearance - set to air Wednesday following prime-time convention coverage and a televised address by Republican vice presidential nominee Paul Ryan - was primarily aimed at younger and women voters whom the Obama campaign has been courting all week.

Democrats have been urging both constituencies to pay close attention to the GOP convention and the party platform, which they described as "extreme."

Letterman asked the first lady about recent controversial comments by Republican U.S. Senate candidate Rep. Todd Akin of Missouri, who falsely claimed in an interview last week that victims of "legitimate rape" rarely get pregnant.

"When you have a guy, and I don't want to embarrass anybody… like Todd Akin, and, for whatever reason, he says something that he wishes he hadn't said, and there's some embarrassment, is it a big deal? Is it not a big deal?" Letterman asked. "I don't know, dumb guys are allowed to say dumb things?"

"That's how guys are," Michelle Obama joked.

Asked whether she and the president ever talked privately about Akin or other politicians who say "dumb things," the first lady was coy.

"There are moments when there are interesting things that happen, and we discuss them," she said. "There are times."

Obama's sit-down with Letterman, billed by the White House as an "official" appearance to promote her nutrition and fitness initiatives, was her third in as many years.

While in New York City today, the first lady also taped episodes of "The Dr. Oz Show" and "Rachael Ray" that will air in September, the administration said.