Now the star has taken to Instagram to respond to the controversy, saying she was "not aware" of the organisation's past at the time.
"The century-old organisation that hosted the debutante ball had an unquestionably racist, sexist, and elitist past.
"I was not aware of this history at the time, but ignorance is no excuse. I was old enough to have educated myself before getting involved," she added.
Kemper made it clear she denounces white supremacy and went on to apologise for her actions in the lengthy statement.
"I want to apologise to the people I've disappointed, and I promise that moving forward I will listen, continue to educate myself, and use my privilege in support of the better society I think we're capable of becoming," Kemper wrote.
She explained earlier in the statement that she had intended to ignore the criticism, but decided it was better to condemn her past actions.
"There is a natural temptation when you become the subject of internet criticism, to tell yourself that your detractors are getting it all wrong. But at some point last week, I realised that a lot of the forces behind the criticism are forces that I've spent my life supporting and agreeing with."