"The Big Bang Theory" delivered a Valentine's surprise for its viewers last Thursday night when it revealed that Bernadette was pregnant! By episode's end, only Valentino the rabbit was privy to Bernadette's news, however, it's only a matter of time before the rest of the group find out.

According to showrunner Steve Molaro, the baby reveal will take place in the beginning of the upcoming episode "The Positive Negative Reaction."

"We really dig into the entire group and everybody's reactions to it. They're mostly positive but obviously with some surprise and concern about what this means for the future," Molaro told The Hollywood Reporter.

If there's someone who will react negatively to the news, viewers are right to assume that it would be Sheldon. As expected, Sheldon's reaction will be atypical.

On the other hand, based on the promo image for the upcoming episode, Howard will react beautifully to the news and will share a special moment with his wife and unborn child.

However, sometime later, Howard will begin to worry about having to provide for his child. Given the absence of his father growing up, he will also feel an added pressure to step up in ways that his father never had.

"They're nervous, they're excited and they're not 100 percent ready to go with confidence. So it's fun to see two people who just got on a rollercoaster that they weren't entirely sure they wanted to get on but they're ready to make the best of it," Molaro added.

While the arrival of baby Wolowitz isn't expected until mid-season 10, viewers can look forward to another milestone – the 200th episode.

While plot details for the special event are being kept under wraps, Molaro has revealed that the upcoming episode will be bringing together a lot of previous characters and the episode will feel very much like a celebration.

According to TV Line, Christine Baranski, John Ross Bowie, Wil Wheaton and Sara Gilbert are all due to make an appearance. Furthermore, iconic "Batman" star Adam West will make his first appearance on the show.

Be sure to tune in for "The Positive Negative Reaction" airing on Feb. 18 and the 200th episode titled "The Celebration Experimentation" airing on Feb. 25.

Season 9 of "The Big Bang Theory" airs every Thursday at 8 p.m. ET on CBS.