In December 2003, producer Vidhu Vinod Chopra quietly released debutant director Raj Kumar Hirani's feel good comedy Munnabhai M.B.B.S.

No one expected it to work. But the story of a 40-year-old gangster's efforts to educate himself in medical school found unexpected acceptance.

Munnabhai... starring Sanjay Dutt became one of the huge successes of 2003 and also launched Hirani as a super-director.

Four months later, another debutant director, Farah Khan, has cast mega-star Shah Rukh Khan as an army officer who goes back to school with his sibling, played with perky precocity by Zayed Khan, in Main Hoon Na.

Munnabhai... and Main Hoon Na share some uncanny similarities. Both cast their leading men in the back-to-school mould and leave the mega-stars' open to jokes about age and misplaced youthful zest.

In that sense, Sanjay and Shah Rukh can be both seen redefining their careers in unexpected ways.

Prior to Munnabhai..., Sanjay was typecast as the gangster. In Munnabhai... he was converted into a gangster going against every law of viciousness.

In Main Hoon Na, Shah Rukh, who was himself in high school five years ago in Karan Johar's Kuch Kuch Hota Hai, graduates to being an anachronism on the campus.

Are our heroes finally growing up?

Says Sanjay, I'm 44 and I've no qualms about playing my age. It would look silly if I go around chasing skirts around trees at this age. I've to act my age. Munnabhai... was a funny and effective way of accepting middle age.

Shah Rukh agrees. If you mean am I ready to act my age, then the answer is yes. But I think I could've done both the elder and younger brother's roles effortlessly.

In fact at one point when we couldn't get the right actor to play the younger brother I suggested to director Farah Khan that I play the younger brother while Sunny Deol play the older man. Luckily, we found Zayed Khan just in time. He's perfect for my brother's role.

Besides the back-to-school theme, there are some other similarities too. Shah Rukh was actually the first choice to play Munnabhai... And Boman Irani who found such richly deserved fame as a professor after Munnbhai... is cast again as the principal of the school in Main Hoon Na.