This answer should probably come with the biggest spoiler alert ever, but at the end of season 8, the writers of How I Met Your Mother finally decided to reveal the character that gives the show its title.
Alluded to as "the girl with the yellow umbrella" in previous episodes, the character was finally revealed on the 13th of May 2013 - and is played by Cristin Milioti.
Although she was revealed to the audience, series 8 ended with none of the on-screen characters actually sharing a scene with her - building anticipation for the final series of the hit TV show.
The actress, who has a background in Broadway theater and musicals, was an unexpected surprise to fans of the CBS show, and is tipped to feature heavily in the final 2013-14 series of the show.
In fact, producers of the sit-com have let slip that the narrative and focal point of the show will change drastically with the introduction of 'the mother'.