The 43-year-old actor, who first rose to fame as Russell 'Stringer' Bell in the HBO series The Wire, has not confirmed the reasons behind the sudden break up.
A source told The Sun; 'It ended very recently and it's too soon for her to talk about it... they've kept it very quiet so she's surprised people know already.
'It's very sad that this has happened while Idris is experiencing the highest points of his professional career and they can't celebrate it with each other.'
Idris, who is most recognisable from his role in the BBC police drama Luther, has two children, 13-year-old Isan from a previous relationship, and 22-month-old son Winston with Naiyana.
After the apparent split, the actor will stay living in a separate flat in South West London so that he can be near his son, who was born in April 2014.
According to reports in The Sun newspaper, Idris started dating the 28-year-old make-up artist in the summer of 2013 and they quickly moved in together.
Idris is often seen at red carpet events, and took his teenage daughter as his guest to the SAG Awards in Los Angeles instead of Naiyana.
During his acceptance speech for two awards at the Screen Actors Guild, Idris name-checked a number of people, but not his girlfriend.
When asked if he was single, the London-born-actor said; 'That's the media for you.'
The OBE winner has been married previously, between 1999 and 2003 to Kim Norgaard, the mother of his eldest child, and again in 2006 to Sonya Nicole Hamlin.
Idris has also been voted the Sexiest Man Alive in 2013 by People magazine and ranked in the 100 Most Beautiful People In The World in 2007.
He is currently filming for Pixar's Finding Dory film and Disney's Jungle Book remake.