Okla. Stat. tit. 85A, § 117

Every employer and insurance carrier who schedules any employee as a person employed by the employer for the purpose of paying or collecting insurance premiums on a workers' compensation insurance policy or who pays, receives or collects any premiums upon any insurance policy covering the liability of such employer under the workers' compensation law by reason of or upon the basis of the employment of any such employee shall be estopped to deny that such employee was employed by the employer.