John Cusack is a would-be boyfriend in multiplexes this month in Must Love Dogs. Anyone who wants to keep up with him as he guides a tour of Chicago must love riding a bike.

The guy on the bike is famous, but he's not right now. Zipping up and down the skyscraper streets, along the famous lakeshore, and through the heady arts, restaurant, and nightclub districts of Chicago, he's no longer best identified as John Cusack, one of the most venerable actors of his generation. Returning to the city where he grew up, Cusack reverts to the role he loves most. He becomes just another Chicagoan, another guy on a bike in awe of the city sprawling beneath his pumping feet.

"Chicago is the best-kept secret in America, in a weird way," he says. "It's an international city, and you have all the great ­architecture and all the stuff that any major international city would have. But it still has a great, down-home, down-to-earth, almost no-nonsense sensibility. They don't suffer fools well."

Which is why Cusack's favorite way to see Chicago is not from some stupid sports car or silly limousine but from the seat of a bike. And even though America's third-largest city stretches across 229 square miles, Cusack insists that the heart of the city is easily navigated.

"It's a great city for biking around," he says, rattling off streets, sites, secret places. "I do it on a little half mountain, half electric bike called the Wavecrest."

So, with the wind in his hair and his grip on the handlebars of his Tidalforce Spike bike from Wavecrest, Cusack takes us on a tour of his hometown, the City of Big Shoulders, the Windy City, Frank Sinatra's kind of town.

Cusack is calling from a hotel in Los Angeles in the middle of a daylong studio promotion for Must Love Dogs, the romantic comedy in which he stars this month with Diane Lane and Dermot Mulroney. He says he's had a very long day, filled with one interview after another, with photo sessions interspersed.

"So, we're going to talk about Chicago," I say, and I can hear him brighten.

"Hit me," says Cusack.