"What goes up must come down," Akshay Kumar says softly, philosophically, invoking Isaac Newton while speaking of his own career graph.

It's been a rough year for the actor. After tremendous hype, the megabudgeted Chandni Chowk To China was an utter commercial and critical failure. Tasveer 8x10 met a similar fate, and while Kambakkht Ishq had an opening that ensured it wasn't a complete commercial loss, the film was savaged by critics and far from being a hit.

And this must be far from what Kumar, 42, is used to these days. Over the last four years, he has steadily gone from strength to strength, toppling the Khans in both box office consistency as well as acting fees.

The Akshay Kumar genre, much like the industry-dominating Govinda films in the 1990s, has enjoyed success despite critical bashing and mostly mediocre screenwriting. Kumar's tremendous screen presence has seen things fall into place, his goofy-hero persona warmly and unerringly striking a chord among the audience.

Now comes Blue, one of the year's biggest budgeted releases. Directed by newcomer Anthony D'Souza, the film stars Sanjay Dutt, Lara Dutta and Zayed Khan alongside him, but neither of those stars have enjoyed recent box office success. Nope, the pressure for this one's squarely on Akshay. Again.

Not that he shows it. Sitting poolside at a Mumbai hotel, itself in turn just a few feet away from the beach, Kumar is the very picture of unflappability.

"Blue is a film we haven't seen in India before. I don't think we make too many thrillers in India, and this one is underwater. It's also a very interesting script. It's a treasure-hunt movie, and I thought we haven't seen something like that for a long time. The stunts are great but the idea of a treasure hunt excited me a lot. I really did this film for my son, I think he'll love it."

He goes on to rave about Blue's soundtrack, which includes a song, Chiggy Wiggy, featuring pop superstar Kylie Minogue.

"Blue has great music. It is one of the top three, top five soundtracks of my career, along with films like Dhadkan," he says, but one gets the sense he feels obligated to praise the only time he's worked with A R Rahman.

Singh Is Kinng saw Snoop Dogg rapping about Kumar, and he hugged Sylvester Stallone in Kambakkht Ishq. Will Kylie prove lucky for him? The music has had a surprisingly lackluster start. Despite deafening airplay, it is widely considered the Oscar-winning composer's most generic-sounding work, and just hasn't taken off.

Yet Kumar is certainly a man of his own opinion. He still defends Chandni Chowk To China, saying he has no idea what went wrong, and still enjoys watching it on television or DVD.

"Nobody knows about it. No, actually, I'm sure many people know about it, the critics know about it, but I don't know about it. I tried my best on it, I worked very hard and I don't know where it failed. I still enjoyed being a part of it and I would still say Nikhil Advani is one of the finest directors I've ever worked with."

Lip service? Perhaps, but the grapevine has it that Kumar has signed Advani on to helm his home production.

Akshay agrees that films like Singh Is Kinng and Chandni Chowk To China were projects where he came first, and everything else, including the script, was secondary.

"But none of the other films were like that. I tried to do a Tasveer 8x10, tried something different, it didn't work either. It's not about what is going to work and what is not going to work. It's about trying to get different scripts and me trying to experiment, that's more and more important. Even Blue, or the films after that, Action Replay and De Dhana Dhan, these films are not basically so-called 'hero' films."

Ghajini, last year's biggest hit, and Wanted, 2009's big hit thus far, both regress into an old, brainless dishoom-dishoom formula -- a formula Kumar himself perfected in his Khiladi movies. Is the action hero tempted to return to the hardcore masala movie?

"No, I'm trying to do something different. I tried doing it in Tashan, but then again it didn't work for me," he says.

Newspapers splashed pictures of Kumar and Shah Rukh Khan a few days ago when the latter visited Akshay on the sets, and while Kumar is justifiably fed up of the hue and cry over actors meeting, he is quick to squash rumours of a project brewing between the two.

Yet while he's decidedly the biggest fish in Blue, he says he enjoys collaborating with actors and is completely open to multistarrers. "Yeah, why not? All my life I've done that. I've worked with A-listers when I was B, and with B-listers when I was A."

Kumar, widely recognised as the fittest actor in the industry despite being two decades older than the freshest kids on the block, likes pushing himself physically.

Director Nagesh Kukunoor is wide-eyed with admiration for Kumar not just picking up Parkour at his age, but being so good at it, and the upcoming Blue sees him do all sorts of insane things, mostly a couple of hundred feet below sea level. "Wait and see," Kumar grins. "It's fun stuff."

It's not been the finest of years for Akshay, but he is one of the rare actors who doesn't get defensive about reviews. "They do their part, and my part is just to absorb it and go ahead."

There is a genuine air of the unschooled in his approach, one willing to listen, and as he repeats his trademark line about how critics were kind enough to call him wooden in his early years when he feels he was a furniture showroom, there is a sense that the man takes his stardom with more than a pinch of salt.

"I know very well that things that go up must come down," Kumar says, slowing down, rocking his chair onto its back legs. "And a graph that goes up has to come down. So it's okay. It's not the first time it's happened to me. Three or four times my graph has gone up and down, so it doesn't matter. It moves on. I move on."

And then he breaks into a big grin, that famous irresistibly naive grin, when asked about the possibility of even momentary frustration.

"You know, I came to this industry with just Rs 5,000, so I can't ever be frustrated at all. I think what I have is more than I've ever expected in my life," he says.