The Titanic actress, 37, married the fellow Brit, 34, "in early December in New York," according to a source. "They were surrounded by a small group of friends and close family members."
A rep could not be reached for comment. The two were first linked in the fall of 2011.
This is the third marriage for Winslet. The Reader actress was wed to director Jim Threapleton from 1998 to 2001; they are parents to daughter Mia, 12. Winslet and director Sam Mendes tied the knot in 2003 and divorced seven years later; they are parents to son Joe, 9.
Rocknroll, the nephew of Virgin billionaire Richard Branson, was previously married to British socialite Eliza Cowdray, the daughter of a multimillionaire viscount.
In September 2012, Winslet and Rocknroll (born Abel Smith) purchased a 15th-century home in West Sussex, England. "Ned is really happy with Kate," a source once told Us of the couple. "He feels he can learn so much from her."
This article originally appeared on Usmagazine.com: Kate Winslet Marries Ned Rocknroll!