TORONTO - "Pirates of the Caribbean: On Stranger Tides" may have grossed over $1 billion across the globe, but most critics despised it and it didn't have the same spark with American audiences.  One of the big reasons why may have been the absence of Keira Knightley and Orlando Bloom who appeared in the first three films.  Knightley in particular developed quite a rapport with series star Johnny Depp in the last two pictures. Speaking to Knightley at the 2011 Toronto Film Festival on Sunday, this journalist couldn't even propose a return for the expected fifth and sixth installment without an immediate "No" from Knightley's smiling lips.

Knowing moviegoers might have company in hoping she might return I followed up with, "If Johnny Depp called up and says, 'Come on, please just make a cameo?'"

Knightley smiles again and without flinching replies. "No. I said when the second one came out that there wasn’t going to be another one for me.  I mean, they were already shooting the third one at that time.  I knew that that was going to be it for me.  It was an extraordinary experience, you know, but I was 17 when I started it and 21 when I finished.  And that’s quite a large chunk of time there.  And, you know, they are amazing people, but I’ve always wanted to act because I like changing.  I like exploring different things.  And I sort of feel like I’ve done the pirating thing, as wonderful as it was and it was amazing."

Instead,  Knightley has been stretching her acting talents in dramas such as "Never Let Me Go," "London Boulevard," "Last Night" and her acclaimed performance in David Cronenberg's "A Dangerous Method" which is screening at the festival.  Knightley's thoughts on that difficult role will be visited closer to the film's release, but she was clearly excited about the recent announcement she'll soon be working again with her "Atonement" and "Pride & Prejudice" helmer Joe Wright on a new version of "Anna Karenina."  The film will also star Saoirse Ronan who will also be marking her third collaboration with Wright after "Atonement" and "Hanna" (which Knightley admitted she still hadn't been able to catch). What about Wright's directing style makes the two ladies so keen on working with him?

"I don’t know.  It’s an amazing thing.  It’s a bit like Viggo [Mortensen] and David [Cronenberg]," Knightley says. "When you find directors, you find creative collaborations that really work.  And I don’t know why it works between me and Joe. We’re working really hard at the moment and hopefully 'Anna Karenina' will work.  You never know, it needs a bit of the wind in the right direction and a bit of luck and everything.  But we’ve had a great time the other two times we’ve work together."

Knightley continues, "You know, I think it’s a personal thing.  I’ve worked with John Maybury a couple of times and got a couple of other directors who were looking for other projects as well.  It’s an amazing thing when you find people who you’ve worked with once and there is a collaborative spirit and an energy.  It’s really exciting."

"Anna Karenina" is about to begin production for a 2012 release.  "A Dangerous Method" will hit theaters on Nov. 23.

For year round entertainment news and commentary follow Gregory Ellwood on Twitter @HitFixGregory.