Our aim is to confirm the nature of the long period radial velocity measurements for \beta Gem first found by Hatzes & Cochran ( 1993 ) .
We present precise stellar radial velocity measurements for the K giant star \beta Gem spanning over 25 years .
An examination of the Ca II K emission , spectral line shapes from high resolution data ( R = 210,000 ) , and Hipparcos photometry was also made to discern the true nature of the long period radial velocity variations .
The radial velocity data show that the long period , low amplitude radial velocity variations found by Hatzes & Cochran ( 1993 ) are long-lived and coherent .
Furthermore , the Ca II K emission , spectral line bisectors , and Hipparcos photometry show no significant variations of these quantities with the radial velocity period .
An orbital solution assuming a stellar mass of 1.7 M _ { \odot } yields a period , P = 589.6 days , a minimum mass of 2.3 M _ { Jupiter } , and a semi-major axis , a = 1.6 AU .
The orbit is nearly circular ( e = 0.02 ) .
The data presented here confirm the planetary companion hypothesis suggested by Hatzes & Cochran ( 1993 ) . \beta Gem is the sixth intermediate mass star shown to host a sub-stellar companion and suggests that planet-formation around stars much more massive than the sun may common .