After Fox officially announced that the "Prison Break" revival will be a full-blown season, news about the returning cast members are starting to emerge.

Lead stars Wentworth Miller and Dominic Purcell have already announced that their characters Michael Scofield and Lincoln Burrows will return for the series revival. But the fate of two other fan-favorite characters are still being discussed.

According to a report from Express, actress Sarah Wayne Callies and actor Robert Knepper are still negotiating and are yet to finally announce their participation in the upcoming series revival.

In her previous interviews, Callies said that she was doing everything to squeeze in the production schedule of "Prison Break" so she can reprise her role as Sara Tancredi in the series.

"They're trying to make it work, I'm trying to make it work - it's a bit of Tetris with everyone's schedules because we all have other jobs," the actress previously told Digital Spy, as quoted by Express.

Knepper's reprisal of his role as the vile psychopath Theodore Bagwell in the series is still being fixed, but fans of the show are hoping to see T-Bag return to the show.

The "Prison Break" revival was planned to be a 10-episode limited mini-series. According to Fox co-chairperson/CEO Dana Walden, "The story unravels on an international landscape — it's not a domestic [plot]. We open on a very international contemporary-feeling story."

But while the plot for the series revival/season 5 is still under wraps, rumors claim that the story will focus on the fake death staged by Michael during the fourth season finale.

According to Forbes, the upcoming episodes will explain why Michael decided to stage his own death, and what really happened with his brain surgery. Fans would also want to know what he did during the whole time that he was believed to be dead.

The fifth season of "Prison Break" will start production in March.