20 CFR § 404.331 - Who is entitled to wife's or husband's benefits as a divorced spouse.
You are entitled to wife's or husband's benefits as the divorced wife or divorced husband of an insured person who is entitled to old-age or disability benefits if you meet the requirements of paragraphs (a) through (e). You are entitled to these benefits even though the insured person is not yet entitled to benefits, if the insured person is at least age 62 and if you meet the requirements of paragraphs (a) through (f). The requirements are that -
(a) You are the insured's divorced wife or divorced husband and -
(d) You are age 62 or older throughout a month in which all other conditions of entitlement are met; and