Doubt about Primary keys and tables

I have 2 tables:

CREATE TABLE OFICINA (

DNI_T NUMBER NOT NULL,
NAME VARCHAR2 (20),
SURNAMES VARCHAR2 (40),
SOU NUMBER,
CARREC VARCHAR2 (15),
CONSTRAINT OFI_PK
PRIMARY KEY (DNI_T) );

and...

CREATE TABLE ESPECTACLE (

DNI_T NUMBER NOT NULL,
NAME VARCHAR2 (20),
SURNAMES VARCHAR2 (40),
ESPECIALITAT VARCHAR2 (20),
PREU NUMBER,
CONSTRAINT ESPECTA_PK
PRIMARY KEY (DNI_T) );

The problem is ¿Which must be the relation between the primary keys of the 2 tables? ¿I add a foreign key (DNI_T) in ESPECTACLE ? Or I have to create other table that contains both primary keys (one would be name changed).