In a statement to celebrity news Web site TMZ, OK! Editor-in-Chief Sarah Ivens said the magazine had "spent a heartbreaking day with Britney Spears and witnessed first-hand an emotional cry for help that will leave you shocked and sad."
"This week, on newsstands Friday, the truth will be told," Ivens said.
The statement was posted Tuesday on TMZ's Web site. A day earlier, TMZ said it had "learned that Britney's self-arranged photo shoot and interview with OK! Magazine was a complete disaster" and that her behavior during the interview was "nothing less than a meltdown."
OK! publicist Brian Strong said the magazine wouldn't publish photos of Spears from the shoot due to legal reasons. He said OK! would deliver "a very real account" of its interview with the 25-year-old singer.
The Associated Press was attempting to locate a representative for Spears.
Earlier this month, Spears apologized for attacking a photographer's car with an umbrella in February, saying at the time she was preparing to try out for a movie part and got carried away.
The incident took place during the same period in which Spears shaved her head, got new tattoos and was seen partying hard in Los Angeles clubs.
Not long after, the erstwhile pop star, more recently derided as a pop tart for her highly public forays into midnight carousing, checked into a monthlong stay in rehab.
Spears filed for divorce from aspiring rapper Kevin Federline in November, just two months after giving birth to the couple's second child, Jayden James. Their older son, Sean Preston, was born in September 2005.