The 42-year-old musician - who was previously married to Gwyneth Paltrow - has told friends that he's no longer in a relationship with Dakota, who is best-known for starring in the 'Fifty Shades' movies.
A source told The Sun newspaper: ''Chris and Dakota were very easygoing and always seemed really happy together.
''There was talk of engagement but now he says they have gone their separate ways, which has come as a real surprise to everyone.''
The high-profile duo dated for 20 months and had previously discussed tying the knot.
Last year, an insider described their romance as ''serious''.
The source shared: ''They will probably get married. It's serious.
''Chris (likes that) she doesn't thrive on the spotlight and is very understated.''
Meanwhile, Gwyneth previously revealed plans to write a book about her experiences of divorce.
The Oscar-winning actress - who is now married to Brad Falchuk - went through a divorce from the Coldplay frontman in 2016 and she now wants to pen a tome about her experiences with Chris, because she thinks their bond is special.
Gwyneth - who has kids Apple, 15, and Moses, 13, with Chris - said: ''Both Chris and I have made a commitment to continue to love the things about each other that we've always loved and to really continue to develop our friendship and to find ways to continue to communicate. There's been a long process to it.
''At some point maybe I'll write a book, because you really have to focus on forgiveness and spite that comes up; you have to let it go.''
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