Big Brother’s Sarah Jane and Mary Kalifatidis surprise Katie as they reveal they’ve been hiding

‘The old bags are back!’ Big Brother’s Sarah Jane Adams and Mary Kalifatidis surprise Katie Williams as they reveal they’ve been hiding in a secret room

It’s ‘Surprise Week’ in the Big Brother Australia house.

And on Wednesday night’s episode, Katie Williams was in for the shock of her life when she was making her daily diary entry.

Evicted housemates Sarah Jane Adams and Mary Kalifatidis left the 27-year-old fitness trainer speechless when they revealed they were still in the competition. 

Up here! Big Brother’s Sarah Jane Adams and Mary Kalifatidis took fellow housemate Katie Williams, 27, (pictured) by surprise when they revealed they’ve been hiding in a secret room

Speaking of SJ and Mary’s departure, Katie said: ‘It feels different. The dynamic has changed. The mother energy has disappeared in the house. I’m feeling flat today.’ 

Big Brother then said: ‘I have a message from two of your fellow housemates, actually how about they tell you themselves?’

The evicted housemates then appeared as they looked down from a hole in the attic which was adjacent to the diary room.

Surprise! Evicted housemates Sarah Jane Adams and Mary Kalifatidis left the 27-year-old fitness trainer speechless when they revealed they were still in the competition

Surprise! Evicted housemates Sarah Jane Adams and Mary Kalifatidis left the 27-year-old fitness trainer speechless when they revealed they were still in the competition

'The old bags are back!' The evicted housemates then appeared as they looked down from a hole in the attic which was adjacent to the diary room

‘The old bags are back!’ The evicted housemates then appeared as they looked down from a hole in the attic which was adjacent to the diary room

‘Katie we love you baby. We heard what you were saying about us,’ SJ said.

‘You weren’t expecting the old bags to be back. Did you?’ Mary continued, before Sarah told Katie to ‘Soak it in.’

The pair continued: ‘Were in the attic. It’s like my house, it’s all timber, spiders [and] it’s got a wireless radio.’

'Katie we love you ... We heard what you were saying about us,' SJ said. 'You weren't expecting the old bags to be back. Did you?' Mary continued, before Sarah told her to 'soak it in.'

‘Katie we love you … We heard what you were saying about us,’ SJ said. ‘You weren’t expecting the old bags to be back. Did you?’ Mary continued, before Sarah told her to ‘soak it in.’

Shh! Upon leaving the diary room, Katie told Marley Biyendolo (pictured) and Jess Trend

Shh! Upon leaving the diary room, Katie told Marley Biyendolo (pictured) and Jess Trend

‘We can tune in and hear everything that you’re all saying. It’s like, we’re in the room, but we’re not in the room. It’s fantastic … We’re here, but let’s not waste our time.’

The pair then warned Katie that Nick Benton, Daniel ‘Danny’ Hayes and Melissa ‘Mel’ McGorman were plotting together and that they needed to keep AFLW player Jess Trend in the house.

Big Brother Australia continues on Sunday at 7pm on Seven 

Plot twist: Big Brother's Sarah Jane and Mary were sent to a secret attic after shocking double eviction during Tuesday night's episode

Plot twist: Big Brother’s Sarah Jane and Mary were sent to a secret attic after shocking double eviction during Tuesday night’s episode 

Look up! 'My house has surprises around every corner, but did you ever think to look up?' the mysterious Big Brother voice-over told the evicted guests

Look up! ‘My house has surprises around every corner, but did you ever think to look up?’ the mysterious Big Brother voice-over told the evicted guests