When the producers of "How I Met Your Mother" talked about adding a new character for its 100th episode, they didn't mention that they would cast an actress as established as Rachel Bilson. The former "The O.C." star has been hired for a one-time stint, although many believe that she would fill in the pivotal role of the mother.
In September, Executive Producer Craig Thomas told EW that in celebration of the milestone, the show will get some serious "mother action" during the episode. He added, "It'll be the closest Ted's ever come to [discovering who she is]. He's getting a step closer every episode this season, and episode 100 [we] kind of go bananas with it."
Thomas' production partner Carter Bays also shared the same kind of clue regarding the episode, saying "Ted will also get as close to meeting the mom as he's ever before. I don't want to give it away, but he gets so tantalizingly close, it's ridiculous."
For one thing, Bilson's rep has confirmed that she won't be a recurring role. Thus, the possibility of Bilson being the mother is not yet crystal clear.