The firm said it would not make her name public.

According to e-mails the woman sent to Palfrey on her Akin Gump account, she "enjoyed and even missed" the work she did at night for Palfrey, who has been charged by federal prosecutors with running a large scale prostitution ring.

"Perhaps not the weekly grind, but was thinking that a day a week would be fun and spa money," the legal secretary wrote to Palfrey last year, after Palfrey had closed her business and was considering whether to re-open it.

Palfrey said the Akin Gump secretary would at times "answer the phones" and assign women on nights when Palfrey was unavailable.

Palfrey has pled not guilty to the charges against her, maintaining her escort service, Pamela Martin and Associates, provided "legal, fantasy sex" and nothing more.

The Akin Gump secretary was described by Palfrey as an "absolutely lovely gal," who was working as an escort "to go back to school and get her education, to finish her college degree."

"We had no inkling until she informed us this Monday morning," said R. Bruce McLean, the chairman of Akin Gump.

The woman, who worked directly for one of the firm's many prominent lawyers, has been placed on administrative leave.

The firm has a policy prohibiting full-time employees from holding any other jobs. "She did not seek approval for that particular job and would not have been given it," McLean said.

McLean said the woman told the firm she was a government witness in the D.C. Madam case, and the firm was hesitant to dismiss her because of that.

According to the e-mails provided to ABC News by Palfrey, the Akin Gump woman was interested in helping to restart the escort service after Palfrey had closed it, suggesting it could be done from the Akin Gump offices.

"It is a shame to basically throw away over a decade of hard work and contacts," she wrote last October, just before federal agents raided Palfrey's operation.

"I think that handling the phones 4 to 5 nights a week is a very fair offer and would be something that I could easily do, even with my paralegal duties as they could pretty much be done simultaneously in front of a computer," she wrote.

A lawyer for the woman, Athan Tsimpedes, said his client "never took over the business." He said his client "does not want the publicity that Ms. Palfrey desperate seeks."

Considered one of the most powerful firms in Washington, Akin Gump partners make up a who's who of Washington insiders, including Vernon Jordan, former Speaker of the House Tom Foley, former Secretary of Health and Human Services Tommy Thompson, former Republican National Committee Chairman Ken Mehlman and co-founder Robert Strauss, an adviser to numerous presidents.