One of the critical factors why TV shows last for a lifetime is cast chemistry. The longetivity of a series usually depends on the key cast members liking each other because shooting such shows takes around 16 hours a day, meaning they spend a lot of time with each other. Imagine a set of people having to work that long and not have any hint of liking to each other. That would definitely be hell. On the other hand, if a cast is well united and are working harmoniously, they'd eventually grow close and become a family.

On highly popular series, the actors really don't have a choice but to like each other. Take into consideration Beverly Hills 90210. But then again, Shannen Doherty, who was not her real sane self during those days, is probably just a plain exception to the rule. Nonetheless, the relationships built because of that show seem to remain strong as the 1990s turned into the millennium. Take a look at the crowd of Dancing with the Stars where Beverly Hills 90210's Ian Ziering was a contestant and you'll see familiar 90210 faces.

Among the audience this week were celebrities Tori Spelling, Jennie Garth, and Jason Priestly, who were all in support to Steve Sanders, Ian Ziering. Last week, Gabrielle Carteris and Brian Austin were in attendance to lend their moral support. Ian isn't one of the favorites to win on the show, but he is challenging. He is in good shape, and may be able to land a spot in the final two or three. Nonetheless, it is heartwarming to see his former cast mates watching and showing their support for the actor.

Friends of Ziering and the entire original cast of Beverly Hills 90210, excluding Doherty and Luke Perry were in attendance in the last two weeks. Cynics may say that the cast members were there just because they're not in the limelight anymore, but it would be better to think that it was their friendship that stood the test of time, thus the heartwarming support for Ziering. Beverly Hills 90210 is one of the most iconic shows on television, and it's really good to see the cast members together again.