Dave Grohl and the Foo Fighters are in Toronto to promote their new album In Your Honor. (Ernest Doroszuk, SUN)

Dave Grohl's teenage rock 'n' roll fantasy didn't exactly come true, but he can still die a happy musician.

The Foo Fighters singer-guitarist and former Nirvana drummer had Led Zeppelin bassist John Paul Jones play piano and mandolin on two different songs on the just-released new Foos album, In Your Honor.

Then, to top that off, Grohl was invited by Jones to sit with the Zep contingent when the British rockers got a lifetime achievement Grammy earlier this year in L.A.

"That honestly was the most special thing that had ever happened to me in my life, musically, that day," said Grohl, 36, during a promo visit here yesterday as he remembered the Grammy event. "There was a part of me that always thought that playing drums in a Led Zeppelin reunion would be the highlight of my life -- I think it's any drummer's fantasy -- but then after just hanging out with them for one day, that was enough."

Jones ended up on In Your Honor -- a double CD of electric music (mostly inspired by the crowds that Grohl met while campaigning for two weeks with U.S. presidential candidate John Kerry) and acoustic songs -- when Grohl came up with a wish list of 15 to 20 guests.

Originally, Grohl wanted Jones to play mellotron on one song, and although it was recorded, it didn't make the final cut.

"It was my fault, not his, he did a great job. I thought the lyrics were shitty," says Grohl.

And, yes, intimidation was a factor.

"Absolutely," he says. "The guy's just a musical f---ing prodigy. He's a genius. To have him come in and listen to your song and chart it as he's listening to it and then go in and do two takes on the piano! I mean, just watching him work was amazing. But knowing how much of a heavyweight he is really did spook me a little."

Another guest on the acoustic record -- singer-pianist Norah Jones -- was much harder to fathom in rock circles.

"Before anyone had heard the album, that was the first question in every interview: 'What the f--- is Norah Jones doing on your album? Or Snorah Jones, as people call her. But I think now that people have heard the record they understand this song (Virginia Moon) is her territory more than ours, and it only made sense that we had someone like her involved -- because it's not every day that we play bossa nova."

Nirvana fans, meanwhile, will be thrilled to hear Friend Of A Friend, which Grohl wrote in 1990 when he had just moved behind the drum kit for Nirvana.

"It was when I first moved up there to Olympia, Wash., and was living with Kurt (Nirvana singer-guitarist Kurt Cobain)," said Grohl. "I wrote it about Kurt and Krist (Nirvana bassist Krist Novoselic). They were strangers to me. I didn't know those guys when I joined the band. And that was the first song that I ever wrote on an acoustic guitar."

On a much lighter note, Grohl just heard and saw Canadian crooner Paul Anka sing his swing version of Nirvana's Smells Like Teen Spirit on David Letterman recently.

"I remember it wasn't until half-way through the first verse that I thought, 'Holy s---! That's Teen Spirit.' And I thought it was f---ing amazing," said Grohl."I thought it was so great. It was such an interesting arrangement. It's pretty classic. Did they have irony in the '60s? I don't know."