diff --git a/NAMESPACE b/NAMESPACE
index b58765ecc1..281ab36b35 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -84,6 +84,8 @@ S3method(guide_geom,default)
 S3method(guide_merge,default)
 S3method(guide_train,default)
 S3method(guide_transform,default)
+S3method(heightDetails,ggplot)
+S3method(heightDetails,ggplot_built)
 S3method(heightDetails,titleGrob)
 S3method(heightDetails,zeroGrob)
 S3method(limits,Date)
@@ -146,6 +148,8 @@ S3method(vec_ptype2,mapped_discrete.double)
 S3method(vec_ptype2,mapped_discrete.factor)
 S3method(vec_ptype2,mapped_discrete.integer)
 S3method(vec_ptype2,mapped_discrete.mapped_discrete)
+S3method(widthDetails,ggplot)
+S3method(widthDetails,ggplot_built)
 S3method(widthDetails,titleGrob)
 S3method(widthDetails,zeroGrob)
 export("%+%")
diff --git a/R/utilities-grid.R b/R/utilities-grid.R
index c231f0b279..2ea3d10951 100644
--- a/R/utilities-grid.R
+++ b/R/utilities-grid.R
@@ -67,3 +67,15 @@ height_cm <- function(x) {
     cli::cli_abort("Don't know how to get height of {.cls {class(x)}} object")
   }
 }
+
+#' @export
+widthDetails.ggplot <- function(x) widthDetails(ggplotGrob(x))
+
+#' @export
+widthDetails.ggplot_built <- widthDetails.ggplot
+
+#' @export
+heightDetails.ggplot <- function(x) heightDetails(ggplotGrob(x))
+
+#' @export
+heightDetails.ggplot_built <- heightDetails.ggplot