At least not according to a rep for Mendes, who calls rumors that the British filmmaker has been carrying on a relationship with Vicky Cristina Barcelona actress Rebecca Hall "ridiculous."
Hall, 27, met Mendes, 44, in 2006 on the set of Starter for 10, an indie film Mendes produced. They've been seen together more recently in London and New York, where they were reportedly working on productions for his Bridge Project theater company.
But more than friends?
"Utter nonsense," says Mendes' rep, Simon Hall (no relation to Rebecca, FYI). "Untrue and ridiculous."
Mendes and Winslet, who won a Best Actress Oscar last year (but not for her role in the Mendes-directed Revolutionary Road), revealed on Monday that they were separating after nearly seven years of marriage.
—Additional reporting by Whitney English
We were sorry to add this seemingly happy couple to our Big Celebrity Splits gallery.