Transcript for 'The Bachelor' Finale: Sean Lowe and Catherine Giudici to Wed on TV
Reporter: The bachelor's creator mike fleiss has long harbored his own fantasy. One of ply dreams a couple will fall so padly in love during the course of production when it comes time to see the final rose that they demand justice of the peace be present and get married right often the spot. Reporter: Monday night it almost came true because following this proposal tying a quick knot was on sean and catherine's want to get married mind. If it was up to me I'd go to the courthouse and get it dong. Just so happens I am ordained. we got about 12 minutes left. We could do this. Reporter: Instead they say they'll be exchanging vows here on abc. Date to be determined. From the 1969 wedding of tiny tim and miss vicki on "the tonight show." To 2011 kim's kris on e! It's not like they can guarantee a lifetime sean and catherine will be the fourth couple and spin-off to get free alterations. December 2012 it was j.P. And ashley. Bachelor host chris harrison doing the honors. The bachelor phenomenon is about watching real feelings unfold on television. And fans are invested. Reporter: Back in 2010 it was jason and molly getting soaking wed via an ocean much side service that didn't leave a dry eye or dress or seat back in the house. Along with christa and ryan, first of their kind to do "i DOs" WITH MUCH ADO ALL THE Bachelors woosome twosomes who wed in prime time are still going strong. Can millions of witnesses help a marriage stay together? With millions of fans watching and sending their love, sending their well wishes, you are bound tol that so who knows? It might make a difference. Reporter: For "good morning america," chris connelly, abc news, los angeles.
This transcript has been automatically generated and may not be 100% accurate.