The film leans on a truly electrifying chemistry between the two leads, Saif Ali Khan and Rani Mukherjee. Mukherjee is very appealing and natural and performs brilliantly throughout the film, but it is Saif Ali Khan who steals the show big time. Playing a trendy, humorous, carefree yet gracious womaniser, Khan seems to be tailor-made for the role of Karan, which gives him ample scope to showcase his superb comic-timing and never-seen-before acting skills. He performs with natural ease, infusing the part with the right amount of depth, wit and energy, and always appearing so real and effortless that it can be rightly concluded that no one else would have been able to do it as well as he did. This is an exceptional, unforgettable performance and, according to me, one of the greatest comic-dramatic performances in history.
In support, Rishi Kapoor is very enjoyable in one of his finest and funniest performances. Kirron Kher is outstanding and simply hilarious in an all-out comic part as the loud and loving mother. Rati Agnihotri is as beautiful as ever in a smaller part, and Jimmy Shergill and Isha Koppitar provide great support. The soundtrack, as already mentioned, perfectly suits the film's mood; the title song is particularly beautiful. Please note, Hum Tum is definitely not a rip-off of When Harry Met Sally, as some people have suggested. There are some tiny similarities in the general concept but nothing more than just that, and it has pretty much a story of its own. Finally, Hum Tum is a lovely and memorable film. It is both very funny and moving, and is overall a heartwarming picture which can always be a great watch for the entire family.