What do Justin Bieber, President Obama, Taylor Swift and Queen Elizabeth II have in common? They have all made headlines this year crashing weddings. While many brides wouldn’t be angry if these celebs crashed their wedding day — check out our list of celebrities that you don’t want showing up unannounced at your wedding.

> The Knot’s guide to spotting a wedding crasher

> Taylor Swift crashed the wedding of her boyfriend’s cousin

> How to deal with wedding crashers

Apparently Taylor Swift and boyfriend Conner Kennedy have some wedding etiquette skills to brush up on.

The Boston Herald is reporting that Taylor Swift and her new boyfriend Conner Kennedy attended the wedding of Kyle Kennedy to Liam Kerr — against the wishes of Kyle’s mother, Victoria Gifford Kennedy.

According to the Herald:

“A source at the hotel reported seeing Swift being asked to leave the Fairmont Copley Plaza hotel where Kyle Kennedy, the daughter of the late Michael Kennedy and Victoria Gifford Kennedy, was celebrating her marriage to Liam Kerron Saturday. So we rang up Vicki for the 411.

“They texted me an hour before the wedding and asked if they could come,” Vicki Kennedy said. “I responded with a very clear, ‘Please do not come.’ They came anyway. … I personally went up to Ms. Swift, whose entrance distracted the entire        event, politely introduced myself to her, and asked her as nicely as I could to leave. It was like talking to a ghost. She seemed to look right past me.”

But Swift’s spokeswoman Paula Erikson insisted it was not true.

“There is no truth to that,” she said. “Taylor was invited to the wedding and the bride thanked her profusely for being there.”

Riiiight. Although it sounds like that even if the bride was cool with Taylor showing up to her wedding, momma Kennedy wasn’t. And I have to say, in the case of a formal wedding at the Fairmont in downtown Boston in the midst of New England’s socialites, I can kind of sort of see Mrs. Kennedy’s point.

> 10 ways to spot a wedding crasher

> How to deal with wedding crashers