Past midnight inside a downtown Manhattan recording studio, Sheryl Crow and Stevie Nicks are listening intently to two old recordings of the Fleetwood Mac song "Crystal." Though Lindsey Buckingham performed the vocals on the 1975 "Fleetwood Mac" album (and also on the 1973 pre-Mac duo album, the long-out-of-print "Buckingham/Nicks"), Nicks is going to re-record it, singing the lead for the first time. In this case, precision will be important. A film montage in "Practical Magic" has already been created to match the original tempo, and the new version needs to sync up with it perfectly.

By the second verse, Nicks, leaning against the studio's rear door, is singing along with her disembodied former partner. Leaning against the studio console across the room, Crow joins in. For a few informal, unrecorded moments, it's as if Sheryl Crow has joined Fleetwood Mac.

That -- according to Crow -- would be a dream come true. "Oh my God, when I was a kid I wanted to be her," Crow says in a later conversation about producing music for Nicks. "It's definitely a new and intimidating and exciting prospect. So, I hope I don't suck."

Earlier in the week, Danny Bramson, the music supervisor for "Practical Magic," had given Nicks a call, asking if she'd contribute some tracks on the spur of the moment. Nicks, who doesn't like to work in a hurry, was hesitant about recording a song for a movie that was set to hit the theaters about six weeks later. But she had one suggestion. Since she and Crow were in New York to tape back-to-back VH1 "Storytellers" episodes, they might be able to toss off a quick collaboration.

Even after Crow agreed to be the producer, there was another catch: Both singers were so busy that they could only get together to record the songs in one night, with a brief follow-up the next morning. After that, Crow was off to Europe to promote her new album "The Globe Sessions." Despite the tight schedule, they decided to try it anyway.

In the studio, Nicks finds herself breaking some of her usual recording traditions. "You take four days to get drum sounds," she says, getting nods of agreement from an entourage of backup singers and assistants. "You take days to get guitar sounds. But we're not doing that here. We're saying, well, no time for that -- next job! Which, in its own way, is the greatest way to make music. There's nothing contrived about it... The first album that (Fleetwood Mac) made, we made in three months, and then all the rest of 'em took at least a year. So if I could go back to recording an album in three months, or two months, I'd be delighted."

Across the room, Crow is recording the rhythm section, proving that it's possible to simultaneously chew bubblegum, smoke, and give detailed instructions about when to play brush strokes and when to play rim shots. She seems both meticulous and self-effacing, correcting her players -- many of whom she worked with on her own album -- and then adding, "I'm sorry I'm so f---ing bossy!"

"She's very organized," says Nicks, underscoring the obvious. "You have to be. You can't be la-la-la-la like me and be a really good producer."

"Crystal" is just one of the two tracks they'll cut tonight and tomorrow. The other, "If You Ever Did Believe," will be the first single off the soundtrack. That one had never been cut before, but its demo also dates back quite a few years. How far back? Crow does the calculation. "This one was about Mick (Fleetwood)," she says. "So what does that make it? '78?"

Crow mentions that she plans to contribute background vocals to the two cuts the next day. Though she has some concern that record company restrictions might get in the way, ultimately it isn't a problem. "They really want me to be happy right now," she says, alluding to the fact that her label, A&M, is banking on her new album to revive its fortunes. "So I'm not gonna worry about the politics."

At 3 a.m., they're still toying with the tracks. Nicks doesn't like to sing much past midnight, and had threatened to go home hours ago. But the chance to work with Crow has kept her here. Not without some visible strain, however. Weary of singing her own song over and over again as the bass player and drummer play along, Nicks takes a moment to sing an opening snippet of Crow's song "Strong Enough."

"God, I feel like hell tonight," she croaks, adding, "Ain't that the goddam truth!"

Crow laughs, answering through the control booth mike, "That's why none of my songs are cover-able. I always throw in one line no one else will sing. Would Shania Twain sing that?"

Well, maybe not. But then, Crow's style never seems to hinder her career. Sometime before sunrise, she's got the production in good shape, and she and Nicks call it quits. The next morning, before Crow hops on the Concorde for Europe, they have two songs in the can and an agreement that Crow will produce Nicks' next solo record. Shania, eat your heart out.

Thanks to Debbi Radford for sending this article to the Nicks Fix