diff --git a/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/PnPProblem.cpp b/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/PnPProblem.cpp
index c61d0ea3c5..0978da9b7e 100644
--- a/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/PnPProblem.cpp
+++ b/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/PnPProblem.cpp
@@ -99,6 +99,7 @@ void PnPProblem::set_P_matrix( const cv::Mat &R_matrix, const cv::Mat &t_matrix)
   _P_matrix.at<double>(1,2) = R_matrix.at<double>(1,2);
   _P_matrix.at<double>(2,0) = R_matrix.at<double>(2,0);
   _P_matrix.at<double>(2,1) = R_matrix.at<double>(2,1);
+  _P_matrix.at<double>(2,2) = R_matrix.at<double>(2,2);
   _P_matrix.at<double>(0,3) = t_matrix.at<double>(0);
   _P_matrix.at<double>(1,3) = t_matrix.at<double>(1);
   _P_matrix.at<double>(2,3) = t_matrix.at<double>(2);