ET has learned that the blond beauty is Sophia Thomalla, a 27-year-old German model who is 24 years younger than Rossdale, and one year younger than his eldest daughter, Daisy Lowe, from another relationship. Rossdale is also father to sons Kingston, 10; Zuma, 8; and Apollo, 3, with Stefani.
Take one look at Thomalla's Instagram page and you'll notice that her modeling resume is quite impressive. She's starred in a number of campaigns, including a recent lingerie-clad appearance to promote Axe deodorant, and was photographed for the German edition of Playboy's May 2012 issue.
In addition to modeling, Thomalla also has some dance experience, as she was a contestant on Let's Dance, Germany's version of Dancing With the Stars. She took home the title of Dancing Star in 2010, partnered with Massimo Sinato.
She was later a judge on another dance show, Dance, Dance, Dance, in 2016.
However, while Rossdale and Thomalla's chemistry in the photos appear undeniable, the rocker's rep told ET on Friday that the two are just friends.