"Once Upon a Time" (OUAT) co-stars Jennifer Morrison and Sebastian Stan have broken up. Unlike their fellow co-stars Ginnifer Goodwin and Josh Dallas, Morrison and Stan didn't have a happy ending to their fairy tale love.

According to Us Weekly, it has already been several months since the two stars have split up.

"They broke up at least four months ago," a source told Us Weekly.

"They have gone their separate ways -- no bad blood."

In the summer of 2012, 34-year-old Morrison who stars as Emma Swan in "Once Upon a Time," started dating 30-year-old Stan, who played the Mad Hatter in the same show. Their relationship was not entirely surprising because based on the scenes that they shared on "Once Upon a Time", they have an undeniable chemistry together.

Unfortunately, it didn't last very long. It would have been nice if they ended up engaged, like Goodwin and Dallas, but that would be too much of a real life fairytale.

Not wanting to draw too much attention to themselves, the OUAT co-stars chose to keep a low profile and were rarely seen in public together. That's why the breakup came as a shock. Some people didn't even know they were dating in the first place.

Morrison and Stan seem to have a penchant for dating their costars. Morrison, who used to appear in the TV show "House", dated her co-star Jesse Spencer back then. They were even engaged from 2006-2007 until they broke it off before their wedding date.

On the other hand, Stan used to date "Gossip Girl's" Leighton Meester, who famously portrayed Blair Waldorf in the TV series. This happened after Stan became a recurring guest in "Gossip Girl" as Carter Baizen.

He was also linked to "Glee" star Dianna Agron. Looks like Stan not only likes costars, but also TV stars from hit shows.

Even if Stan and Morrison have chosen to part ways, it looks like there was no third party involved or any other drama that caused them to split up.

"They just grew apart," said another source in the US Weekly report.

Both Stan and Morrison are busy with work not just on TV, but also in the movies. Stan will star in "Captain America: The Winter Soldier" as Chris Evans' friend Bucky Barnes who will become The Winter Soldier. "Captain America: The Winter Soldier" will be shown on theatres in April 2014.

Aside from "Once Upon a Time", Morrison was recently seen as Winona Kirk in "Star Trek Into Darkness."

Read more on other "Once Upon a Time" related news:


Once Upon a Time's Mulan is Bisexual? Questions about Her Sexuality Arise on the Season 3, Episode 3 'Quite a Common Fairy' [PHOTOS] [VIDEO] (Click here)

Once Upon a Time Costars Ginnifer Goodwin and Josh Dallas' Engagement Update: What will the Bride Wear? [PHOTOS] (Click here)