diff --git a/gfx/drivers/gl.c b/gfx/drivers/gl.c
index 0199bd7a9c..c86aae1ed9 100644
--- a/gfx/drivers/gl.c
+++ b/gfx/drivers/gl.c
@@ -3088,9 +3088,17 @@ static struct video_shader *gl_get_current_shader(void *data)
    return (gl && gl->shader) ? gl->shader->get_current_shader() : NULL;
 }
 
+static void gl_get_video_output_size(void *data, unsigned *width, unsigned *height)
+{
+   gl_t *gl = (gl_t*)data;
+
+   if (gl && gl->ctx_driver->get_video_output_size)
+      gl->ctx_driver->get_video_output_size(gl, width, height);
+}
+
 static const video_poke_interface_t gl_poke_interface = {
    NULL,
-   NULL, /* get_video_output_size */
+   gl_get_video_output_size,
 #ifdef HAVE_FBO
    gl_get_current_framebuffer,
 #endif