The news comes just days after the film topped the box office and catapulted the actress into the celebrity stratosphere.
Us Magazine reports that Dakota is now single after she and Matthew decided to go their separate ways...
Dakota, 25, and the Welsh model/singer have been dating since last summer.
An insider said: "Sometime over the holidays, they broke up.
"Her life was getting too crazy and it wasn't something that he wanted to be a part of."
However, it's said that "it wasn't a bad break".
Dakota stars as Anastasia Steele opposite Jamie Dornan's Christian Grey in the hit film Fifty Shades.
The film premiered last week, where Jamie was joined by his wife Amelia Warner.
But Dakota, who is the daughter of Melanie Griffith and Don Johnson, attended the red carpet event alone.
Read Reveal's review of Fifty Shades Of Grey here.
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