(LOS ANGELES) -- Family Guy creator Seth MacFarlane and his Game of Thrones actress girlfriend Emilia Clarke have reportedly split.

A source tells E!, "They are no longer dating. It was really a location challenge. She has been in Europe shooting Game of Thrones and he is based in California, so it was hard to make it work..." The source says the couple remains "friends."

MacFarlane and Clarke began dating last September.  Representatives of both stars have not commented on the report.

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