The Big Brother 2018 star left viewers drooling when she rocked up in a plunging red dress on launch night.
Sian, 25 – who hails from Barnsley, South Yorkshire – left little to the imagination in her gown, which showcased her jaw-dropping cleavage.
However, Sian's looks sparked questions if she's all natural from Big Brother fans.
Speaking exclusively to Daily Star Online, an expert at MYA Cosmetic Surgery dissected Sian's buxom appearance.
"In my professional opinion, I believe Sian has undergone more than one cosmetic/non-surgical treatment including a breast augmentation," they revealed.
"Following childbirth, breasts can often be left with a lack of fullness and breast implants can help bring back fullness and projection.
"Sian's breast augmentation has given her a very natural shape and is in keeping with her feminine figure."
The mother-of-one admitted to spending £4,000 on a boob job and branded it the "best thing" she'd done – but has she gone further?
They added: "It is also possible that Sian has undergone the non-surgical treatment of fillers to her lips as she appears to have fuller lips compared to previous images – especially when smiling.
"The average cost of lip fillers in the UK can range depending on the provider and the amount of filler used, however, you can expect to pay anything from £200 to £1000 per treatment."
It's not just viewers who have fallen for Sian's charms either, Big Brother housemate Isaac Jagroop is smitten too.
The former Ipswich Town footballer already said he wanted to take her on a date but last night Isaac revealed his true feelings.
"I never should have said nothing to anyone about fancying you or whatever," he said, while they were cuddled up in the garden.
"What do you fancy me?" Sian asked.
Isaac then confessed: "Yeah – you're alright."
Big Brother kicks off at 10pm tonight on Channel 5.
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