‘The Big Bang Theory’ season 12 brings in new character Marissa for infertility story line

Lindsey Kraft, previously seen in Dirty John and Grace and Frankie, will play the new wife of Penny's ex Zack

The Big Bang Theory is adding a new character to its cast for its final season.

Lindsey Kraft, previously seen on shows such as Dirty John and Grace and Frankie, will play Marissa, the new wife of Penny’s ex Zack, Deadline reported.

She will return for multiple episodes of season 12, which is set to be the show’s final instalment, as a recurring character.

Penny (Kaley Cuoco) was once married to Zack (Brian Thomas Smith) after tying the knot in Las Vegas, but the pair ended up having their union annulled.

In this new story line, Marissa and Zack will be dealing with infertility.

A newly released log line states that Zack and Marissa both want a child, but as Zack is infertile, they “ask Leonard for help” – though it’s not entirely clear just how the physicist would be able to assist them.

Kraft will make her first appearance on the show on 10 January.

It was confirmed in August that The Big Bang Theory’s 12th season would be its last.

The sitcom, co-created by Chuck Lorre and Bill Prady, premiered in 2007 on CBS and quickly became a staple in the sitcom realm.

By the time it wraps up in 2019, the series will have become the longest running multi-camera comedy in history.

“We are forever grateful to our fans for their support of The Big Bang Theory during the past 12 seasons,” producers Warner Bros Television and Chuck Lorre Productions told The Hollywood Reporter in a statement.

“We, along with the cast, writers and crew, are extremely appreciative of the show’s success and aim to deliver a final season, and series finale, that will bring The Big Bang Theory to an epic creative close.”

The Big Bang Theory‘s 12th season premiered in September this year. Seasons typically run from September to May in the following year.