Mississippi Code Title 11. Civil Practice and Procedure § 11-19-9

Every tenant sued in a civil action seeking ejectment as relief shall forthwith give notice thereof to his landlord, under penalty of three (3) years' rent of the premises, to be recovered by the landlord or his representatives in a civil action. The landlord of such tenant, or any other proper person, shall, by leave of the court or judge, be admitted to appear and defend the action in all cases where the same would have been allowed heretofore, and either separately or jointly with the tenant. Any person admitted to defend as landlord in respect of property whereof he is in possession only by his tenant, shall state in his answer that he defends as such landlord, and such person shall be allowed to set up any defense he has heretofore been allowed to set up, and no other. Any judgment in such action shall have the same effect for or against such person so admitted to defend as if he had been named in the complaint and regularly served with process.