The attorney-client privilege is, in some sense, a broad one. In general, it prevents anyone from forcing a lawyer or client to disclose confidential communications between the two that relate to legal representation. The privilege belongs to the client, meaning that no one else—not even the attorney—can waive it. (For more, see Can my lawyer waive the attorney-client privilege?) But it has exceptions, and it doesn’t mean that all questions regarding the attorney-client relationship are off-limits.
For example, a defendant who testifies at her own trial may have to answer questions about the fact of—rather than the substance of—communications between her lawyer and her. In one case, during cross-examination, the prosecutor asked the defendant whether he had discussed his testimony with his lawyer before taking the stand. The Pennsylvania Supreme Court found this question permissible because it didn’t probe what was said during the conversation, but rather whether the conversation happened. (Com. v. Carson, 559 Pa. 460 (1999).)
However, the Pennsylvania Supreme Court’s ruling isn’t necessarily indicative of the law throughout the country. (See, for example, Haley v. State, 398 Md. 106 (2007) and Blanks v. State, 406 Md. 526 (2008).) Courts are generally very protective when a question in any way touches on what was said between attorney and client.
If you have any questions about whether certain communications are privileged, make sure to ask them of your attorney. Particularly if you plan on testifying in court, ask your lawyer how you should handle any questions that touch upon the attorney-client relationship.