Bollywood Khiladi Akshay Kumar is celebrating his 53rd birthday today. The Bollywood superstar, known for minting hits faster than anybody else, has given a number of memorable films in a career spanning nearly three decades. The only Bollywood hero to make the cut in the list of Forbes' 10 highest paid actors in the world every year, Akshay started his film journey as a lead with Raj N. Sippy's Saugandh in 1991, and has since then featured in over 100 films ranging different genres. Hailed for his versality, healthy lifestyle, choice of films, charming personality as well as his social cause, Akshay is one of the most bankable Bollywood stars today.

While the National Award-winning Kumar is celebrating his special day in the company of his wife Twinkle Khanna and kids Aarav and Nitara in Scotland with the team of his upcoming espionage thriller Bell Bottom, Peepingmoon.com talked to some of the directors he has worked with and asked them to share their experiences and what makes Akshay the unstoppable force. Here's what these filmmakers had to share about Akshay, his work of ethics and the secret behind his massive success:

Vipul Amrutlal Shah (Aankhen, Waqt, Namaste London, Action Replayy) 

Akshay's biggest strength is that he never stops learning. Even today if he meets a new person, a new assistant director doing his first film, and if he says something interesting and unique Akshay immediately registers it and makes it a part of his work ethics. And I think that's incredible quality for somebody to be such a big star and yet so humble and grounded. The other big thing is that he thinks about his entire unit. He very fondly believes that he can choose to do one film a year at this point of time in his career but if he does four films a year then four units get jobs, four sets of distributors get a film to distribute. And if just helps the whole industry's economy. 

Another great thing about Akshay is that he loves to keep the atmosphere on set calm and fun. Whatever can be the stress he can rise above it and keep the atmosphere glowing with his humour and chill out attitude. He will adjust very quickly if there are troubles on the set. He will be the first one to step up. There are so many instances where some co-actor or action guy has injured and he is the first person to rush to their help, even if that means there's a risk involved. The amount of modesty that he has even today is incredible. 

Despite all the success and achievements of his life which are massive Akshay is still very very modest, down-to-earth, and real human being. With him, you can relate on all levels and I think that's his biggest strength. He has worked with the maximum number of debutant directors that I know of. He doesn't look at a newcomer with suspicion, rather he looks at them as an opportunity that this newcomer will bring something novel because he wants to break into the directorial world of the film industry. 

These are a few of the things that, to me, are the secrets of his success. And the fact that I've known him for almost 20 hears and nothing in that long period has changed. Akshay is an incredible sign of a very mature and very settled human being with a great value system. These are the things that set him to be what he is! 

Milan Luthria (Once Upon A Time In Mumbai Dobara) 

Akshay is one of the most positive people I have come across in life. His positivity is infectious and all those working on a film with him feel it and feed off it in the best possible way.

His discipline is also unflinching. To achieve so much and still be up before dawn every single day, finish all meals before sunset, and so many other things to do with health, punctuality, time allocation, etc., all these force those around him to fall into a sound discipline and respect each other’s time.

His willingness to take risks, work with new talent, take on uncharted territories and characters is very encouraging for filmmakers and audiences. If such a big star repeatedly pushes the envelope, many others feel confident doing the same, and new audiences are attracted. He still has a great combination of no ego and an insatiable hunger for more work! 

Tanuja Chandra (Sangharsh) 

When I worked with Akshay, he was known more as an action star and less for his performances. I am glad we were able to collaborate in a film that required a solid and felt performance, filled with emotions. He’s a very hardworking person and he put his heart into Sangharsh. I think it could well be considered one of his most memorable performances which makes me very happy. He was able to bring some soul, even anguish to the character of a criminal and I’m sure he’s proud of that. 

Shree Narayan Singh (Toilet Ek Prem Katha) 

When I think of what makes Akshay Kumar the unstoppable force, only one thing comes to my mind, Discipline. There is not one soul as disciplined like him I have come across. That I feel is one of the major factors why he is able to do what he is doing. He gives everything in his life enough time — be it work, family, etc. And I hope he continues like this for as long as possible.

There are several amazing memories I share with him, what I cherish the most is the kind of support he showed towards me during filming 'Toilet Ek Prem Katha'. Akshay sir is known in the industry to work in 8 hours shift which usually begins early morning but in my case he has worked more than 14 hours too and on some days more than that. His unconditional support towards helping me during the filming of TEPK was out of the world.

As far as any change is concerned I hope he never changes his warmth and kindness towards people and his love for his work. I personally believe that he has a power within him which pushes the people he works with towards their goals. 

Anil Sharma (Ab Tumhare Hawale Watan Saathiyo) 

Akshay Kumar is a grounded person. He came at a time when the actors used to regularly work in 10 to 12 films every year. So he is used to the mentality of seeking multiple projects for himself and helping the industry to grow along as well. He isn’t a self-centered person and knows that the more work you do, the more work the industry will have. He has the gift of knowing the incoming tastes and trends, which is why he moulds his films differently every year. 

I had the pleasure of working with him in 'Ab Tumhare Hawale Watan Saathiyo'. I want to narrate an anecdote of his sincerity. Akshay had sprained his ankle during the shoot and we had a shot where he had to run. Lots of military extras and crowd were there. It was the last shot of the day and was to be done at sunset. If we didn’t do it then we would lose a lot of  money. Akshay realized what was at stake and willingly asked to do it. He requested though that since his ankle was sprained we try to do it in one take. The shot started and Akshay ran with vigour and did not show an ounce of pain, but due to some technicalities, we had to do it again. Akshay did not hesitate. He did take two and then take three all in an effort to get the perfect shot. That determination and sincerity has made him what he is today. I wish him a great birthday. May God bless him and he keeps making great films. 

Anthony D'Souza (Blue, Boss) 

I owe a lot to Akshay sir as he has backed me strongly and always believed in me. As a new director in Blue, he took me under his wing and taught me a lot. He is a force to reckon with due to his sheer dedication and unfathomable energy. His discipline not just on sets but in everyday life is something that sets him apart from the rest. I think he’s one of the few superstars who is always giving young talent a chance to prove themselves. 

Personally, I think he has grown tremendously as an actor and is not scared of tackling subjects that might be looked upon as offbeat or even untouchable. If I might be bold enough to say, to me and my family, he’s been like an elder brother looking out for us and loving us and accepting us into his life. I am forever in his debt and will do anything to live up to his expectations!