Britney: 'I Made A Mistake'

(AP)  Britney Spears has taken responsibility — well, some of it — for driving with her baby son, Sean Preston, sitting in her lap.

"I made a mistake and so it is what it is, I guess," Spears tells "Access Hollywood" in an interview that was to air Thursday.

Several photos published Tuesday showed Spears driving her sport utility vehicle in Malibu, Calif., with her 4-month-old son perched on her lap rather than strapped into a car seat in the back seat.

The 24-year-old pop star said she did it because of a "horrifying, frightful encounter with the paparazzi."

In response, X17, the agency that snapped the pictures, said they were snapped "in a very peaceful context, in which photographers exhibited no aggressive behavior."

"Being put in the situation that I was in, it was kind of bad with the paparazzi," Spears tells "Access Hollywood." "Last week, my mom and I went out and they were on us really bad, so you instinctively do what you need to do."

The Los Angeles County Sheriff's Department has said it won't pursue any charges.

Sean Preston, who was born in September, is Spears' first child. She is married to Kevin Federline, a former backup dancer.