The teenage daughter of former vice-presidential candidate Sarah Palin has split from her fiance for a second time, weeks after getting re-engaged.
Bristol Palin told People magazine: "It's over. I broke up with him."
She said that fiance Levi Johnston had told her on the day they announced they were engaged again that he might have fathered a child with another teenager.
Miss Palin, 19, and Mr Johnston already have a baby son; they first separated last March, shortly after the birth.
The Palin family rose to prominence when Republican presidential candidate John McCain plucked Sarah Palin, then governor of Alaska, from relative obscurity to be his running mate in the 2008 election.
During the campaign, it was announced that Miss Palin, then 17, was pregnant and that she would marry Mr Johnston, an unemployed former high-school hockey player she had met at school.
Their son was born in December 2008, shortly after the election, but they split up in March 2009.
Then they announced on 14 July that they were engaged again, despite not having the approval of their parents.
In the People magazine interview, Miss Palin claims that her ex-fiance appeared in a video mocking her family.
"The final straw was him flying to Hollywood for what he told me was to see some hunting show but [I] come to find out it was that music video mocking my family," she said.
"He's just obsessed with the limelight and I got played."
Mr Johnston has appeared frequently on television criticising Sarah Palin and has courted attention by posing nude in Playgirl magazine.
Sarah Palin resigned from the Alaska governor's office in July 2009 and is now one of President Barack Obama's chief critics, using her Facebook page and frequent appearances on Fox News to target him and other Democrats.
In a statement released to People magazine, Mrs Palin said she hoped her daughter would move forward "with her same forgiving, gracious, optimistic spirit, but from henceforth she'll know to trust but verify".