The American actress, 30, began dating the Mumford & Sons banjo player last year (15) and they went public with their relationship in July, 2015, when they were photographed walking hand-in-hand in Paris, France.
Winston popped the question over the Christmas holidays (Dec15), and on Saturday (15Oct16), the happy couple became husband and wife in a romantic destination wedding, Dianna's representative confirms to UsMagazine.com.
No further details about the nuptials had been revealed as WENN went to press, although the pair is famously private and never even confirmed the rumours of its engagement after the news hit headlines at the start of the year (16). Instead, the actress let her jewellery do the talking as she displayed a large diamond on her left ring finger during an outing for London Fashion Week in February (16).
And an insider reveals the 27-year-old musician always spoil his love whenever he can.
"He is the nicest guy and treats her like a princess," a source tells the outlet. "He is so thoughtful and flies her family everywhere they go and to see them whenever she wants. He is also so good to her friends."
It's the first marriage for both Dianna and Winston.
The blonde beauty clearly has a thing for British boys - she previously dated Magic Mike actor Alex Pettyfer, hunk Christian Cooke and director Henry Joost, while she has also been linked to movie star Sebastian Stan and actor Thomas Cocquerel. Marshall, 27, enjoyed a brief relationship with Katy Perry.
Winston isn't the first member of Mumford & Sons to find love with a fellow celebrity - frontman Marcus Mumford is married to The Great Gatsby star Carey Mulligan.