Did good girl-gone bad Jessica Simpson slip up and get pregnant? Well it appears she at least thought she did.

A panicked Jessica Simpson secretly took an at-home pregnancy test fearing she’d conceived a baby by new love Dane Cook, The ENQUIRER has learned.

“She definitely took an early pregnancy test and, knowing Jessica, she must have been freaking out,” a Hollywood insider revealed.

A surprise pregnancy by the single Simpson could have been the beginning of the end of her popularity. At least Britney waited to be married and we have seen Katie Holmes joy of being pregnant and having a child out of wedlock in Hollywood.

“Jessica is a good girl - and a surprise pregnancy isn’t something she could go to her agent or her parents about. And of course she no longer has Nick to confide in.”

Jessica’s rep denies it, but insiders say the pregnancy scare is the latest bump in Jess’ roller-coaster love life since she shed hubby Nick Lachey and launched a romance with Cook, star of the hit HBO comedy “Tourgasm.”

“Jessica was on the pill for years, but after she split with Nick and had no steady relationship, she went off it,” the insider confided.

After sticking the pregnancy test under her tongue, Simpson decided she was not pregnant.