We present preliminary results of CCD BV photometry of the old open cluster King 2. The values obtained for the main parameters are:E(B-V)=0.31, (m-M)0=13.78, metal content approximately solar, and age 6×109 yr. From the comparison with synthetic colour-mgnitude diagrams generated by models with overshoot we try to answer the question whether or not convective elements generated in the core can penetrate into the surrounding stable zone (separated by a discontinuity of molecular weight).