People.com
By K.C. BAKER
03/27/2014 at 09:00 AM EDT

It’s a Fleetwood Mac lovefest!

After leaving one of the most successful rock bands of all time 16 years ago, Christine McVie is back – and her band mates couldn’t be happier.

“We’re thrilled,” the band’s co-founder and drummer, Mick Fleetwood, tells PEOPLE exclusively. “She’s just the dearest of friends and we’ve remained that way always. We’ve always missed Chris. To have a key, key member return to the fold is huge. It’s really not happened, to my knowledge in any shape or form, on this level.”

McVie, 70, whose songs “Little Lies” and “Say You Love Me” were among Fleetwood Mac’s biggest hits, tells PEOPLE exclusively, “I honestly could never in my wildest dreams have thought I could return to the band. It’s just a dream come true. I go to bed going, ‘This is so great. This is what I’ve been yearning for all these years and I didn’t know it.’ We’re family. We’re very lucky.”

All five members of the band reunited this morning when McVie, along with her ex-husband, John McVie (who is “on the mend” after a cancer diagnosis last year, she says), Fleetwood, Lindsey Buckingham and Stevie Nicks appeared on Today to officially announce the return of the keyboardist and singer/songwriter.

Starting this fall, McVie will join Fleetwood Mac on its upcoming tour, On with the Show, and the band may release a new album “down the road,” she says.

Fans, of course, are thrilled to have her back – and are wondering if there will be any drama, since the band was known as much for its mega-hits as for its feuds and, um, offstage fun.

“Us?” joked Fleetwood.

Says McVie, “Well, it wouldn’t be Fleetwood Mac without a bit of drama, you know. Of course there will be some drama, but for the most part I have to say everyone is getting along really well. At the moment the drama is kind of the fun.”

The British-American band was also notorious for its hookups – and breakups – which they wrote about in numerous songs. Nicks and Buckingham famously broke up, Fleetwood had an affair with Nicks, and the McVies divorced. Considering their history, do they foresee any more inter-band romances down the road?

“God knows we were probably overly open about all that stuff years ago,” says Fleetwood, 66. “But that goose is cooked.”

Why McVie Decided to Return

McVie joined the band in 1970, which her then-husband John McVie and Fleetwood founded three years earlier. In 1975, they were joined by Buckingham and then-girlfriend Nicks, becoming one of the most successful groups of all time, with best-selling albums including Fleetwood Mac, Rumours and Tusk.

After playing with Fleetwood Mac for 28 years, McVie left in 1998. “I think that I was probably just burned out when I left and I was frightened to fly,” she says.

While she released her last solo album in 2004, spending much of her time quietly in England, she says she had no intentions of returning to Fleetwood Mac.

“But then,” she says, “two years ago I started to really miss playing. I was toying with the idea of playing with some little band or … I didn’t know what, really. The truth of the matter is the only people I wanted to play with were the people I had played with all my life – these guys – Fleetwood Mac.”

She overcame her fear of flying through therapy, boarding a plane for the first time in years in February 2013 with Fleetwood at her side, where she spent time in Maui with him and other friends, watching the Mick Fleetwood Blues Band rehearse for an upcoming show.

She did something else for the first time in 15 years during that Maui trip: She performed onstage at the Maui Arts & Cultural Center with Fleetwood – and Aerosmith front man Steven Tyler, a close friend and neighbor of Fleetwood’s.

When Tyler asked McVie during rehearsals if she was going to join them onstage, she declined, which came as no surprise to Fleetwood, who promised he “would never ask her to play” since she would probably say no.

Still, says Fleetwood, “Chris called me the next morning and suddenly the ambient voice sounded quite small and she said, ‘I was actually just thinking, would you like me to play at the gig?’ I said, ‘Are you kidding me? Of course!’ And that was how we segued into Chris coming up and doing a few songs along with Steven Tyler and my little band.”

The Dinner that Clinched It

Shortly after McVie performed with Fleetwood and Tyler in Maui, she had dinner at Locanda Portofino in Santa Monica, Calif., with the four remaining members of Fleetwood Mac, which convinced her to return to the band.

“Lindsey was saying, ‘The chemistry around the table is so fantastic, you know?’ ” says McVie. “That was the start of it. I think I made overtures to Mick, saying, ‘What would you think if I were to rejoin the band?’ ”

The four members talked it through, telling her they would love to have her back – as long as she meant it. “Lindsey was saying, ‘If you really are serious, then you’ve got to commit.’ It was sort of an epiphany in a way. I just knew that’s what I wanted.”

Preparing for Her Momentous Return

“I’d like to say it’s like falling off a log but it’s a little more complicated than that. My muscle memory needs to return,” she says, explaining that she needs to brush up on the lyrics to the songs that made her famous. “But I also slipped back in to it as though I never left, in a sense. In fact, I actually feel stronger.”

McVie – who wrote many of the band’s most famous hits – is also writing new songs, which could turn up here or there during the tour or on an upcoming album.

“Lindsey has been trolling through some tapes and files I sent to him when I was in England,” she says. “He took bits that I thought were useless and said, ‘That’s fantastic!’ So he’s made them into something that I didn’t realize were really that good. I am going, ‘God. I can’t believe that I actually wrote that.’ ”

Full Circle

McVie says that she can’t wait to start touring again. “It is a celebration and it is a really joyful time for the band. God must have been smiling on me because I feel like a different person. This has done nothing but wonders for me and I love my band so, so much.”