Can I be forced to transfer a domain I legally own if I've made it inactive to satisfy someone with a claim to it?

You have spent very little money and time obtaining this domain name incorporating this celebrity's name, and the advice from the other responders is good - don't pick this fight. The risks of cyberquatting on a celebrity's trademark and publicity rights are huge compared to be small small amount you paid for this domain name, and you seem to be admitting that you want to sell this domain name rights for a profit, which is a violation of the celebrity's rights. Under the cyberquatting and publicity laws, only the celebrity has the right to profit from their names used as domain names. There are exceptions to this rule for 1st amendment uses by legitimate critics of the celebrities, but you have said nothing to indicate that your intended uses are anything but promotional in derogation of the celebrity's own rights. Remember that celebrities are much better positioned than you are to fight this fight.

Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.

Registering, in bad faith, a domain name that is identical or confusingly similar to someone else's trademark violates federal trademark law and the domain name registration agreement entered into by the registrant and his or her registrar. The registration is wrongful even if no content is published on the corresponding web page.

Celebrity names can be, and very often are, trademarks. Assuming that the domain name you registered is the same as, or confusingly similar to, the celebrity's name and you registered the domain name in "bad faith" (See http://tr.im/quRb at Section 1125(d)(1)(B) ) then, yes, you can be forced to transfer the domain name's registration to the owner of the celebrity's trademark (likely a company formed by the celebrity). You are due no compensation for the registration and, in fact, may be liable to the trademark owner for between $1,000 and $100,000.

Oftentimes, however, another's trademark may lawfully be used as part of a domain name. You need to speak with a trademark attorney to get his or her take on the matter. I caution you against publishing any specific information about this dispute in public (such as this website). Good luck.