Seth MacFarlane, the recent Oscars 2013 host, and his Game of Thrones star girlfriend Emilia Clarke have called it quits.

A source told E! that they are no longer dating and that it was challenging for them to date because of distance. "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 despite the distance," the source told E!.

The source added that the 39-year-old Family Guy creator and Clarke, 25, have remained friends.

Clarke will be on Broadway starting March 20 for Breakfast at Tiffany's. On March 4 she debuted at the Cort Theater where she stepped naked into a bubble bath.

A source told the New York Post, "What titillated the audience . . . was a full nude scene between Emilia and [male lead] Cory Michael Smith." The source said Clarke takes off Smith's clothes and he gets in the tub, then she goes off stage, returns in just a towel and then joins him in the tub.

She was recently at the Game of Thrones season 3 premiere on March 18 in Los Angeles.

MacFarlane's hit cartoon series Family Guy was renewed for a 12th season, which will start in September 2013. His other hit cartoon series American Dad is in its eighth season.