The detective, played by Scott McGregor, grows closer to Jade after joining her for a night out at Charlie's Bar - keen to let off some steam following troubles at work.
After reporting another member of the police force for corruption in an upcoming plot, Brennan is disappointed as his colleagues start to turn against him. However, some fun with Jade proves to be the perfect distraction.
Gemma Pranita, who plays Jade, confirmed the surprise new pairing in an interview with TV Week, saying: "They're playing pool and getting on really well, when all of a sudden they find themselves kissing."
Pranita added that her character is risking the wrath of her new friend Kate Ramsay (Ashleigh Brewer), who recently broke up with Brennan but still has feelings for him.
She said: "Jade doesn't consider Kate in that moment, as she knows she's broken up with Brennan and doesn't appreciate that it's just not cool to hook up with other people's exes. But I think Kate will be horrified and shocked and angry."
The plot airs next week in Australia and early June on Channel 5 in the UK.
> Read our Neighbours spoilers and news
> Neighbours updates title sequence