The Family Guy creator had been dating Game of Thrones star Emilia since at least September 2012, and now the two have broken up, according to E! Online.
"They are no longer dating," a source says. "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."
"They have remained friends," the source continues.
Seth, who's 39, and Emilia, 25, were first spotted getting cozy at an Emmy after-party last September.
Seth has had quite the year, between directing the smash hit Ted and hosting the Oscars. Meanwhile, Emilia will soon be seen on Broadway in Breakfast at Tiffany's.
We thought they seemed pretty cute together, so we're bummed that winter has come for these two.
Source: E! Online