"They were kissing and Brad was being super attentive to her," a source told OK! magazine.
"He was in a semi-public place but didn't seem to mind people seeing him. She's a real beauty and obviously a lot younger than him."
Poturalski also bears a striking resemblance to Jolie, 45.
Reports suggest Poturalski and Pitt are spending time together at Pitt's lavish holiday home Chateau Miraval, a vineyard estate he bought for $67 million in 2011 with Jolie.
While not a lot is known about Poturalski, who doesn't post personal details on her social media channels, it is understood she is a mother to a young son.
Boasting over 100,000 Instagram followers, the Berlin-based Poturalski has also been an ELLE magazine cover girl and is managed by A Management modelling agency.
It comes as Pitt and Jolie continue with their messy divorce which has been dragging on longer than their two-year marriage (although they dated for a decade before they wed).
The latest twist in the ongoing saga, which heightened the sheer intensity of their feud, was the revelation that their six children – Maddox, 19, Pax, 16, Zahara, 15, Shiloh, 14, and 12-year-old twins Vivienne and Knox – were absent from Pitt's mother's recent 80th birthday bash at the Fight Club star's Santa Barbara beach house in California.
Sources close to the family said Pitt's parents, Jane and William, hadn't seen their grandchildren for more than four years.
Jolie has reportedly delayed the child custody settlement by trying to get the judge presiding over the case removed.
She is said to have raised concerns over John W. Ouderkirk's lack of transparency concerning previous cases he was hired for involving Brad's lawyer Anne C. Kiley.
Jolie believes Mr Ouderkirk's close connection with Ms Kiley may give her ex-husband an advantage.
