Bonnie Hunt passed on the chance to enter the chatfest arena as Rosie O'Donnell's successor, but the Second City alum gets an opportunity to talk the talk on her new ABC sitcom Life With Bonnie (debuting Tuesday at 8:30 pm/ET). The series finds Hunt playing a mother of three who spends her days hosting a Chicago morning program. The twist? The show-within-the-show's segments are improvised, and feature real guests. In other words, those Italian chefs in the pilot — they're the real deal.

"I love the [talk show] format," Hunt says, "and for me, [Life With Bonnie] is a chance to be able to do something fresh and funny, but not do it every single day — and [not] have people on whose movies I don't really like but pretend I do. That would be painful for me. That's why I couldn't do [Rosie's] job, because I would last about a week."

On Bonnie, Hunt's alter ego will instead play host to "everyday people" — with a few exceptions. Former X-Files agent David Duchovny, who starred in the 2000 Hunt-directed romantic comedy Return to Me, will appear as a local weatherman who's also a filmmaker. "We do have plans to have some of our [actor] friends on to promote movies that are coming out," she explains. "[But they're] actually fake movies and we will have fake movie clips."

Back in the real world, Hunt is quite the seasoned talk show guest herself. In particular, her rollicking visits with David Letterman are always Must-See TV. What's the secret to their pitch-perfect chemistry? "I usually try to do something [unplanned] on the show," she says. "I do a pre-interview and then I go out there and talk nothing about anything that we discussed in the pre-interview. I find it's more fun for me to have him off guard."