"I've never done that before," Nicks said. "It's like a whole new door opening. Now I understand why Lennon and McCartney wrote together."
Rather than record the album in a studio, Nicks opened up her large 1930s Los Angeles home with a fireplace and a view, making the process more fun and relaxed -- the spirit of which, she said, ended up in the album.
"What we've done is contagious," she said, explaining the excitement that has been building over this album. "When you're around a group of people who are creative and super happy, you get contact happy from them."
Stewart has also been Tweeting about the process for the last 10 months, getting the fans excited.
"My fans have been kept in the loop about this whole thing," Nicks said, adding that she doesn't do Twitter or Facebook.
Before the album's May 3 release, Nicks will begin touring in March with old friend Rod Stewart.
The idea for the 16-date tour came last year from Stewart's daughters Ruby and Kimberly.
"They love Stevie," he told Rolling Stone. "She's just ultra-cool -- she has a cult."
Stewart's daughters span the generations, just like Nicks' fans. She says at concerts, she will get "little Rhiannons," women in their 30s who were babies when her hit song "Rhiannon" came out and are now playing it for their teenage daughters.
"I'm so glad that all these people have really great taste in music and have passed it on to their children," she said.
Nicks will open the show with solo tunes and Fleetwood Mac classics, followed by a Stewart set. And they will sing together, possibly Nicks and Henley's 1981 duet, "Leather and Lace."
Eventually, there will be another Fleetwood Mac album and tour. But for now, Nicks is focused on her new solo album.
"I'll let it go as long as it goes, wherever the train takes us," she said. "And when it's done I will regroup."
"I pretty much go back and forth," she said about the group she says is like family. "It's good for me, because I get bored easily. I get to go back to something new again. It's always good to have two outslets."
Here's a quick look at what's become of her former bandmates in Fleetwood Mac, who were inducted into the Rock and Roll Hall of Fame in 1998:
British drummer Mick Fleetwood is the only remaining original member of Fleetwood Mac, a group that was formed in London in 1967 by Peter Green, who combined the names of two of his bandmates, Fleetwood and John McVie.
Bassist McVie didn't play on the band's first single or even at the first concerts of Fleetwood Mac, but, like many others, he would come and go with this group with an ever-changing lineup. During its most successful period, from the mid 70s to the late 80s, the group was comprised of McVie's wife, keyboardist and singer Christine McVie, Fleetwood, Buckingham and Nicks.
Fleetwood was twice married to Jenny Boyd, the younger sister of Patty Boyd, who was married to George Harrison and, later, Eric Clapton. He has faced an addiction to cocaine and personal bankruptcy despite making millions with Fleetwood Mac.
Today, at 63, Fleetwood continues to make music on his own, as well as with the group. In 2010, his album "Blue Again" was nominated for a Grammy Award.