Barney and Robin’s wedding on “How I Met Your Mother” is starting to sound like a pretty legen- -- wait for it -- dary affair. Since filming started on July 10, the cast and crew have been tweet-happy, posting photos from set and teasing guest appearances. So who is the latest star to join in on the fun? Actress Ellen D. Williams!

Williams took to her Twitter on Thursday to share her exciting “How I Met Your Mother” news:

“Look who’s back! #HIMUM #BestPeopleEver #TableRead


Ellen D. Williams has been featured in numerous episodes of “How I Met Your Mother” as Patrice, Robin’s arch-nemesis. Fans will remember that in season eight Barney began to date Patrice, but it was all really a ploy to win Robin back and propose to her on the top of the WWN rooftop. With season nine set to be the “longest wedding weekend ever,” we can only assume that Patrice was invited to the wedding for her part in getting Barney and Robin back together.

Other guests set to appear at Barney and Robin’s wedding include Barney’s brother James (Wayne Brady); Peculiar Jacques, who is a fictional Canadian version of Weird Al; an attractive, available and unfortunate woman named Cassie (Ellie Kemper); and, of course, Cristin Milioti’s “mother"!

Thanks to a photo taken by Robin’s Cobie Smulders, “How I Met Your Mother” fans also know that poor lonely Ted won’t be alone in his hotel room at the Farhampton Inn over the wedding weekend.

When “How I Met Your Mother” returns in September, Josh Radnor’s Ted will still be hiding a pretty big secret from his friends: He’s moving to Chicago after the wedding. Needing time to get away from Robin and look for a new start, we know that Ted will head to the Farhampton train station after the wedding. And it’s there that Ted will meet Cristin Milioti as “the mother.”

The recently leaked synopsis for episode four seems to hint at Ted’s upcoming meeting with his future wife. According to SpoilerTV, episode four is called “Last Time In New York.” Could this be the episode where he packs his bags and goes to the train station, anticipating his last time in New York before moving to Chicago?

Season nine of “How I Met Your Mother” returns for a special hour long premiere on Sept. 23. What are your thoughts on the final season? Let us know in the comments section.