The popular character will soon bow out from the Ramsay Street serial after less than a year as Scott McGregor has decided to leave the role.
As revealed earlier this month, Brennan makes his departure in a special real-time episode of Neighbours which focuses entirely on a 30-minute timeframe.
"A beloved character was leaving us. We didn't want him to go out with a whimper. We wanted him to go out with a bang," Bower told TV Week of the special episode.
The instalment in question sees Brennan tell on-off partner Kate Ramsay, played by Ashleigh Brewer, that he is going into witness protection due to his involvement in a police corruption investigation.
After hearing the news, Kate has just 30 minutes to decide whether she wants to leave with Brennan or stay behind in Erinsborough.
Bower said: "[The episode] features about half a dozen people, but it's mainly about just two - Mark and Kate."
The soap's boss added that McGregor and Brewer were both "terribly excited" to be involved in the episode.
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