After announcing that she is pregnant with baby number 4, speculations about Jessica Capshaw's character in "Grey's Anatomy" season 12 are starting to come out online.

Capshaw made the announcement via Instagram, saying: "The holidays have certainly arrived... All of our lives are being added to by the lights, music and the cheer!! This year our family has reason to further broaden our smile... baby number four is on the way! I am a lucky, lucky girl!"

The actress portrays the role of Arizona Robbins in the series. Arizona just recently divorced Callie Torres (Sara Ramirez), in season 11.

Fans are wondering if Capshaw's pregnancy will be written into the plot of "Grey's Anatomy" season 12. Since the actress did not reveal how far along she currently is, some were thinking that her baby bump will be noticeable as the season progresses.

But the long-running medical drama is known for working with pregnant cast members in the past, so there could be a chance that Capshaw's pregnancy will be hidden until the end of the season 12 production.

Meanwhile, series executive producer Shonda Rhimes recently admitted that she is surprised that everyone on the set of "Grey's Anatomy" is still having fun despite being on air for a long time.

In an interview with Rhimes and the rest of the female leads stars of all her shows in Entertainment Weekly, the executive producer said, "For me especially, season 12 [of Grey's Anatomy] has been an absolute blast. Season 12! How much fun we've been having is really lovely."

The remaining second half of "Grey's Anatomy" season 12 will premiere with the episode titled "The Sound of Silence," which is directed by award-winning actor Denzel Washington and written by Stacy McKee. The episode will air on Thursday, Feb. 11, 2016.