So the band is into its encore, and has already borrowed a tune from the Rolling Stones, when it comes time for the inevitable. It takes only a few chords, the first few ripples of the song, and the sold-out crowd at the Rams Head Tavern in Annapolis is whooping with excitement.

"Well, I gotta cut loose . . . ''

And there, in the center of the stage, is an almost-46-year-old Kevin Bacon, getting jiggy once again with the song that made him a teenage heartthrob back in 1984. His hair is shaggy, his shirt is partly unbuttoned, his hips are swiveling in a pair of truly worn Levi's, and let's face it: The fans love it. So, yeah, this isn't what Bacon had in mind when he and his big brother, Michael, formed the Bacon Brothers, their folk/rock/country/soul band, a decade ago. And it's not what you get for most of the show.

But Bacon long ago succumbed to the inevitable: You can't dance your way around an abandoned warehouse, rocking those hips to a teenage anthem of rebellion, then expect to get away with becoming a musician without throwing in a little "shake it, shake it for me."

Want proof? Up near the stage, just off to the right, a woman can't sit still. She's tapping her feet, she's snapping her fingers, her shoulders are rocking back and forth to the music and she looks as though she's having the most fun she's had all night.

She's Kevin's big sister Elinor.

"Oh, I loved it," she gushes when asked later about "Footloose." "Kevin brought the soundtrack over before the movie came out, and I was listening to the thing on the cassette and I loved it."

She stops, shakes free of her rapture.

"But I love them all," she quickly adds. "I love Michael's 'Don't Lose Me Boy,' which he wrote for his son, and Kevin's songs about his children and his wife . . ."

But there it is: Even big sis can't resist the song that first introduced her brother to the big time.

So the band's in the dressing room before showtime, with the usual sprawl of buffalo wings and something-or-other dip and a half-eaten burger sitting out on the table, suitcases tumbled over each other in the corner, and a last-minute hunt for a replacement guitar underway (Kevin's appears to have gone missing). It's the first night of a brief, 10-day tour the Bacon Brothers are doing, with two appearances in Annapolis followed by two at the Birchmere in Alexandria -- at 7:30 p.m. today and tomorrow -- before heading to Atlantic City and then New York, their home town. Bacon is sitting on the couch, explaining how he just decided to have fun with the whole movie star thing. He's no fool; he knew the critics would be eager to savage him, to paint him as yet another celebrity who thought he could rock. So he decided to poke the beast himself.

"Look, I just figured it was going to come up," Kevin says. "And I didn't want to really pretend that I wasn't an actor. So by playing the song . . . actually, when we first started playing I used to talk about being an actor a lot more."

Two boys raised in a household with four sisters in Center City Philadelphia, Kevin and Michael have been tight since childhood, despite the nine-year age difference. Kevin hit Michael in the head with a melody flute when he was just 2 years old. ("It's metal, it's sharp, it hurt," Michael says. "He let it go," Kevin chips in.) Michael first taught Kevin to play the guitar when his little brother was 12.

"He showed me how to play a few chords," Kevin says. "Taught me how to play 'Hey Jude.' "

Michael was clearly the family musician -- he still remembers the day, at age 8, when he got his first cello -- and he went on to have several bands before building an accomplished career scoring films (he won an Emmy for his work on "The Kennedys"). But Kevin freely admits he harbored all kinds of rock-star fantasies as a kid.

"I was not really even a movie fanatic," Kevin says. "I took an acting class because I wanted to try it out and my brother was already doing the music thing, and I fell in love with acting. I also thought music was really hard. Learning how to play an instrument. It's impossible for me to read music. And it makes your fingers hurt. It's just too much work."

The band came about in 1994, when Kevin was between film projects and he and Michael decided to try their hand at writing some songs together. Again. This, apparently, was a long-standing Bacon boys scheme. Never mind that Kevin was now a movie star, with films such as "A Few Good Men" on his resume and "Apollo 13" on the horizon.

"We'd get together and write songs, and usually with the songs we had some kind of agenda about making a bunch of money," Kevin says. "A get-rich-quick scheme. So we'd write a song about some novelty thing. Roller disco or preppies or safe sex or whatever it was. Then we had this idea it would be easy to write a country song, so we tried to write a country song."

But then a friend asked them to play together at a charity event in their home town, and they hesitantly agreed. From there, they added some more band members, started writing more songs and slowly added some small gigs. They titled their first album "Forosoco," a word that stands for folk, rock, soul and country, the elements they blend in their music. The most recent one, their fourth, is also a DVD and was recorded live last year.

"I think, intuitively, we saw that if we wanted to become successful, we had to do it that way," Michael says of starting out without trying to trade on his brother's celebrity status. "In some ways, though, it is a get-rich-quick scheme, only it hasn't quite happened that way."

Kevin laughs.

"Yeah," he says. "Only we haven't gotten rich and it hasn't been quick."

A guitar has been located, courtesy of -- how convenient is this? -- the guitar shop directly across the street from the Rams Head. Actually, the owner is lending Kevin several. The first set is in full swing, the audience heavily populated with women.

The playlist is a mix of new songs and old, the James Tayloresque tunes written by Michael, such as his favorite, "Don't Lose Me Boy," and Kevin's popular loud, rocking "I'm So Glad I'm Not Married."

Over the course of the 10 years, some critics have been harsh and some have been extremely receptive. Self-deprecating when it comes to his musical talents, Kevin saves his outrage for those who resort to making breakfast meat puns out of their last name. ("The Bacons sizzle," he and Michael say with a snort, mentioning one of the most frequently used headline constructions. Then there are the "Bacon bits." The references to them "bringing home the Bacon." Consequently, they are perpetually on what they call the "No Food Jokes Tour.")

"I think there's always that resistance," Kevin says of the idea that he could be a serious musician. "Always, always, always. I think there still is. My theory is that most people think that music is hard and acting is easy. Most people think they can act. I don't think that most people think that they can just get up and play."

But, hey, he's going to keep getting up and playing. Why? Because it's fun. Because, he says, it gives him those "butterflies" he hasn't had in a while with his acting, no matter how much he still loves his primary career. He sees nothing at all odd about delving into a deep, intense role such as the detective he played in the critically acclaimed "Mystic River" last year, all the while writing songs in his trailer between takes.

Most of the songs are drawn from the brothers' own experiences, and from their friends and their families. Both are married (Kevin to actress Kyra Sedgwick); Kevin has two children, Michael one.

"You can use reality, you can use the truth as a jumping-off point, but you don't have to stay completely true to the reality," Kevin says. "We've got a song called 'Angelina.' My wife's name is Kyra, and I didn't write this song about a girl named Angelina, I . . . "

Michael breaks in.

"Sure you didn't."

Kevin smirks.

"Honey," he says in a syrupy voice, "just so you know . . ."

And then they're both laughing.

Which is a part of why they still do this. They love the music, but they also love hanging out together. Kevin describes a perfect night on the road as the band in the bus with booze, food and no distractions.

"We've always been an extremely close family," Michael says.

So close, in fact, that one of the next gigs the Bacon Brothers are booked for is . . . a wedding.

"Our niece demanded it," Kevin says. "And it's not the first time, either."

The niece, it turns out, is Elinor's daughter. Elinor lives in D.C. and plans to attend all four nights of her brothers' performances in the area. After the first set Monday night, she goes back into the dressing room for a visit. A small group of women -- all older than 40 -- sidle up to the closed door, trying to talk members of the crew into getting them autographs. The women are, obviously, a key part of the Bacon Brothers' audience. They come for the music, yes, but they also come to see Kevin, who still favors those white, sleeveless, ribbed shirts, who still has the engaging smile and the crinkly eyes, who can still carry off a good shake of the hips.

Who still makes them swoon.

The Bacon brothers know how to play to that. "There are certain songs people really want to hear," Kevin says before the show, when a crew member pops in with the night's list.

Like what?

" 'Only a Good Woman,' " Michael and Kevin answer, their voices on top of each other.

"Only a Good Woman" is a country-blues song about a dad's advice to his son, which boils down to "find a good woman and she'll make you a man." Written by both brothers, it's witty, it's fast-paced, it's chock-full of pop-culture references that clearly amuse the audience.

It also happens to be the song where Kevin puts down his instrument and, well, shakes it. A lot.

"It's gotten us through a lot of gigs that weren't going that well," Michael admits.

So it's the go-to song?

"Definitely," Kevin says.

"It's our Mariano Rivera," Michael adds.

"That," Kevin says, "and 'Footloose.' "

Of course.