Now for some REAL sibling rivalry! Sisters Cate and Bronte Campbell will face off against each other for gold after they both qualify for the final 100m freestyle final

Australian Cate Campbell has broken her second Olympic record in just one day after becoming the fastest qualifier for the 100m freestyle final.

Cate took out her semi final after clocking 52.71 following her earlier record-breaking time of 52.78 seconds in the heats.

Her younger sister Bronte Campbell has also qualified for the final after clocking 53.29 in the first semi final.

She has qualified fifth fastest in Thursday night's final where the sisters will battle it out for the Gold medal.

Australian Cate Campbell has broken her second Olympic record in just one day after becoming the fastest qualifier for the 100m freestyle final

Australian Cate Campbell has broken her second Olympic record in just one day after becoming the fastest qualifier for the 100m freestyle final

'I'm confident within myself... it's just about executing good race plans,' Cate said.

'I eased up but then I caught a glimmer out of the corner of my eye, the speedy Canadian was coming through. Wow she is a young kid and swimming incredibly well.'

Cate kicked off the qualifying heats for Australia by smashing the Olympic record when she completed two laps of the pool in 52.78 seconds earlier in the day.

Bronte finished nearly a second slower at 53.71 seconds, coming third to Sweden's Sarah Sjostrom and America's Abbey Weitzeil in heat six.

Cate flashed a cheeky grin as she surfaced and realised her phenomenal record-breaking achievement. 

Bronte looked like she was going to cinch second place but touched the wall 0.17 of a second after Weitzeil who led the heat in the opening seconds of the race. 

Cate took out her semi final after clocking 52.71 following her earlier record-breaking time of 52.78 seconds in the heats

Cate took out her semi final after clocking 52.71 following her earlier record-breaking time of 52.78 seconds in the heats

Cate took out her semi final after clocking 52.71 following her earlier record-breaking time of 52.78 seconds in the heats

Cate took out her semi final after clocking 52.71 following her earlier record-breaking time of 52.78 seconds in the heats

Bronte Campbell has also qualified for the final after clocking 53.29 in the first semi final

Bronte Campbell has also qualified for the final after clocking 53.29 in the first semi final

Bronte finished second in her 100m freestyle semi final with a time of 53.29

Bronte finished second in her 100m freestyle semi final with a time of 53.29

There were concerns for Bronte coming into the Games as she had been burdened with a shoulder injury, but they dissipated after she gave a strong performance in her leg of the 4x100 freestyle relay, where the sisters led the team to gold.

'You are almost more nervous for your first swim than you are for your final swim,' Cate told Seven. 

'It's just good to get out the blocks, start racing and looking forward to getting some more tonight,' she added. 

Bronte said she felt like she was in a 'good position' coming into tonight's final. 

'It's pretty good, just getting through the rounds at this stage it's a very quick field,' she said.

Cate Campbell (pictured) kicked off the qualifying heats for Australia by smashing the Olympic record when she completed two laps of the pool in 52.78 seconds

Cate Campbell (pictured) kicked off the qualifying heats for Australia by smashing the Olympic record when she completed two laps of the pool in 52.78 seconds

Cate had a strong start and led the race from the outset before smashing the Olympic record

Cate had a strong start and led the race from the outset before smashing the Olympic record

Cate flashed a cheeky grin as she surfaced and realised her phenomenal record-breaking achievement

Cate flashed a cheeky grin as she surfaced and realised her phenomenal record-breaking achievement

There were concerns for Bronte coming into the Games as she had been burdened with a shoulder injury, but they dissipated after she gave a strong performance in her leg of the 4x100 freestyle relay 

There were concerns for Bronte coming into the Games as she had been burdened with a shoulder injury, but they dissipated after she gave a strong performance in her leg of the 4x100 freestyle relay 

The Malawi-born swimmers - who moved to Australia from Africa in 2001 - became the first sisters to make Australia's Olympic swimming team since 19

The Malawi-born swimmers - who moved to Australia from Africa in 2001 - became the first sisters to make Australia's Olympic swimming team since 1972

The Malawi-born swimmers - who moved to Australia from Africa in 2001 - became the first sisters to make Australia's Olympic swimming team since 1972. 

They played a large part in setting a new world record of 3:30.65 in the women's 4x100m freestyle relay. 

Bronte said she was just happy that she was able to give her sister a lead to defend when she handed over to her to finish the last leg.

'It was amazing, I barely had any breath left, just enough to cheer her home. It was great going into it knowing that I gave her a lead,' Bronte said. 

The sisters played a large part in setting a new world record of 3:30.65 in the women's 4x100m freestyle relay where Australia claimed gold earlier this week 

The sisters played a large part in setting a new world record of 3:30.65 in the women's 4x100m freestyle relay where Australia claimed gold earlier this week 

Bronte said she was just happy that she was able to give her sister a lead to defend when she handed over to her to finish the last leg

Bronte said she was just happy that she was able to give her sister a lead to defend when she handed over to her to finish the last leg

'It was amazing, I barely had any breath left, just enough to cheer her home. It was great going into it knowing that I gave her a lead,' Bronte (left) said 

It was amazing, I barely had any breath left, just enough to cheer her home. It was great going into it knowing that I gave her a lead,' Bronte (left) said