YES U CAN LEAVE,BUT UT US BETTER TO INFORM THEM THAT U GOT A NICE JOB AND THEY WANT U TO JOIN THEM,KEEP A GOOD RELATION COS U DONT KNOW IF THE NEW COMPANY IS GOOD OR BAD,U CAN EASILY COME TO UR OLD BOSS N JOIN THEM IF U HVE GOOD RELATION IF U DONT LIKE UR NEW JOB.