There are many bars to changing status and adjusting status, and overstaying the visa is not the only problem. Unlawful employment can create several problems when one seeks to adjust status in the US.
Unlawful employment occurs quite frequently when the line between being a visitor for business and actual employment is crossed. Situations where this commonly occurs for performers and athletes are one-time appearances for which remuneration is paid incorrectly, self-employment, or providing volunteer services for which bonuses are later intended to be paid once a legitimate visa is obtained.
Appearing on Jay Leno to promote a project is fine, but getting paid to host a segment of Disney Channel is probably not. Performing at weddings, bar mitzvahs, and parties is also a problem if you were paid, and it may be a problem if you received something “inkind.”
Appearances to promote a product you endorse–whether it is tennis shoes or soda pop–also need to be appropriately structured so that the activity is not deemed “employment” in the United States.
If there has been unlawful employment, then you cannot change status and must–as a matter of general consular practice–apply for the visa at your home consulate. If, however, you are applying to adjust status based on employment (as opposed to based on a family relationship), then you may adjust so long as the unlawful employment was for less than 180 days since your last lawful admission. USCIS examiners will seem unaware of the fact that the 180-day clock starts after the last lawful admission as opposed to being cumulative from the first admission.
As a result, you may find yourself receiving a request for evidence asking for proof of maintenance of status for all admissions and may even find the adjustment referred for interview. However, a brief memo from a good immigration lawyer usually suffices to solve this particular “training issue.” Something of greater concern is that the filing of an I-485 adjustment application–according to USCIS–does not stop the accrual of unlawful employment.
Therefore, either you must maintain your underlying nonimmigrant status or–if that is not possible, such as in the case of an O1 visa–you must have a valid employment authorization document for all employment.
Unlawful employment is a serious violation, so try to avoid working illegally at any cost.