Sounds like distance has caught up with another Hollywood couple.

Ashlee Simpson and "Boardwalk Empire" star Vincent Piazza, have decided to call it quits after a year and a half of dating. A source close to the pair tells Us Weekly, "There was no bad blood and no third party involved. It was honestly just a long distance relationship and it became too hard to make it work."

Simpson, 28, and Piazza began seeing each other in June 2011 and were already a full-blown couple by September. Over the last few months, the pair was seen spending a lot of time in New York City with Simpson's 4-year-old son Bronx, whose father is her ex-husband Pete Wentz.

Simpson, Wentz and his girlfriend, Meagan Camper, were all together last week to celebrate Bronx's birthday, although Piazza was noticeably missing.

But just because they're ending things, doesn't mean it's for good.

"It's not necessarily forever and they could get back together," the source adds to Us Weekly. "Nobody is to blame. Just the distance."

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