diff --git a/NEWS.md b/NEWS.md
index 6bf14d4615..9d85070388 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* `update_geom_defaults()` and `update_stat_defaults()` can now use `new = NULL`
+  to reset the original defaults (@teunbrand, #4993).
+
 * `ggsave()` no longer sometimes creates new directories, which is now 
   controlled by the new `create.dir` argument (#5489).
 
diff --git a/R/geom-defaults.R b/R/geom-defaults.R
index afd2e598d4..375650f8e1 100644
--- a/R/geom-defaults.R
+++ b/R/geom-defaults.R
@@ -1,13 +1,16 @@
+cache_geom_defaults <- new.env(parent = emptyenv())
+cache_stats_defaults <- new.env(parent = emptyenv())
+
 #' Modify geom/stat aesthetic defaults for future plots
 #'
-#' @param stat,geom Name of geom/stat to modify (like `"point"` or
-#'   `"bin"`), or a Geom/Stat object (like `GeomPoint` or
-#'   `StatBin`).
-#' @param new Named list of aesthetics.
+#' @param stat,geom Name of geom/stat to modify (like `"point"` or `"bin"`),
+#'   or a Geom/Stat object (like `GeomPoint` or `StatBin`).
+#' @param new Named list of aesthetics. Alternatively, `NULL` to reset the
+#'   defaults.
 #' @keywords internal
+#' @name update_defaults
 #' @export
 #' @examples
-#'
 #' # updating a geom's default aesthetic settings
 #' # example: change geom_point()'s default color
 #' GeomPoint$default_aes
@@ -15,9 +18,8 @@
 #' GeomPoint$default_aes
 #' ggplot(mtcars, aes(mpg, wt)) + geom_point()
 #'
-#' # reset default
-#' update_geom_defaults("point", aes(color = "black"))
-#'
+#' # Reset defaults by using `new = NULL`
+#' update_geom_defaults("point", NULL)
 #'
 #' # updating a stat's default aesthetic settings
 #' # example: change stat_bin()'s default y-axis to the density scale
@@ -29,27 +31,71 @@
 #'   geom_function(fun = dnorm, color = "red")
 #'
 #' # reset default
-#' update_stat_defaults("bin", aes(y = after_stat(count)))
-#'
+#' update_stat_defaults("bin", NULL)
+
 #' @rdname update_defaults
 update_geom_defaults <- function(geom, new) {
-  g <- check_subclass(geom, "Geom", env = parent.frame())
-  old <- g$default_aes
-  new <- rename_aes(new)
-  new_names_order <- unique(c(names(old), names(new)))
-  new <- defaults(new, old)[new_names_order]
-  g$default_aes[names(new)] <- new
-  invisible()
+  if (is.null(new)) {
+
+    if (!inherits(geom, "Geom")) {
+      check_string(geom)
+    } else {
+      geom <- check_subclass(geom, "Geom", env = parent.frame())
+      geom <- gsub("^geom_", "", snake_class(geom))
+    }
+    old <- cache_geom_defaults[[geom]]
+    if (!is.null(old)) {
+      new <- update_geom_defaults(geom, old)
+    }
+    invisible(new)
+
+  } else {
+
+    g <- check_subclass(geom, "Geom", env = parent.frame())
+    old <- g$default_aes
+    # Only update cache the first time
+    if (!geom %in% ls(cache_geom_defaults)) {
+      cache_geom_defaults[[geom]] <- old
+    }
+    new <- rename_aes(new)
+    new_names_order <- unique(c(names(old), names(new)))
+    new <- defaults(new, old)[new_names_order]
+    g$default_aes[names(new)] <- new
+    invisible(old)
+
+  }
 }
 
 #' @rdname update_defaults
 #' @export
 update_stat_defaults <- function(stat, new) {
-  g <- check_subclass(stat, "Stat", env = parent.frame())
-  old <- g$default_aes
-  new <- rename_aes(new)
-  new_names_order <- unique(c(names(old), names(new)))
-  new <- defaults(new, old)[new_names_order]
-  g$default_aes[names(new)] <- new
-  invisible()
+  if (is.null(new)) {
+
+    if (!inherits(stat, "Stat")) {
+      check_string(stat)
+    } else {
+      stat <- check_subclass(stat, "Stat", env = parent.frame())
+      stat <- gsub("^stat_", "", snake_class(stat))
+    }
+    old <- cache_stats_defaults[[stat]]
+    if (!is.null(old)) {
+      new <- update_stat_defaults(stat, old)
+    }
+    invisible(new)
+
+  } else {
+
+    g <- check_subclass(stat, "Stat", env = parent.frame())
+    old <- g$default_aes
+    # Only update cache the first time
+    if (!stat %in% ls(cache_stats_defaults)) {
+      cache_stats_defaults[[stat]] <- old
+    }
+    new <- rename_aes(new)
+    new_names_order <- unique(c(names(old), names(new)))
+    new <- defaults(new, old)[new_names_order]
+    g$default_aes[names(new)] <- new
+    invisible(old)
+
+  }
 }
diff --git a/man/update_defaults.Rd b/man/update_defaults.Rd
index e009b99d32..8cb6b7b3f6 100644
--- a/man/update_defaults.Rd
+++ b/man/update_defaults.Rd
@@ -1,6 +1,7 @@
 % Generated by roxygen2: do not edit by hand
 % Please edit documentation in R/geom-defaults.R
-\name{update_geom_defaults}
+\name{update_defaults}
+\alias{update_defaults}
 \alias{update_geom_defaults}
 \alias{update_stat_defaults}
 \title{Modify geom/stat aesthetic defaults for future plots}
@@ -10,17 +11,16 @@ update_geom_defaults(geom, new)
 update_stat_defaults(stat, new)
 }
 \arguments{
-\item{new}{Named list of aesthetics.}
+\item{new}{Named list of aesthetics. Alternatively, \code{NULL} to reset the
+defaults.}
 
-\item{stat, geom}{Name of geom/stat to modify (like \code{"point"} or
-\code{"bin"}), or a Geom/Stat object (like \code{GeomPoint} or
-\code{StatBin}).}
+\item{stat, geom}{Name of geom/stat to modify (like \code{"point"} or \code{"bin"}),
+or a Geom/Stat object (like \code{GeomPoint} or \code{StatBin}).}
 }
 \description{
 Modify geom/stat aesthetic defaults for future plots
 }
 \examples{
-
 # updating a geom's default aesthetic settings
 # example: change geom_point()'s default color
 GeomPoint$default_aes
@@ -28,9 +28,8 @@ update_geom_defaults("point", aes(color = "red"))
 GeomPoint$default_aes
 ggplot(mtcars, aes(mpg, wt)) + geom_point()
 
-# reset default
-update_geom_defaults("point", aes(color = "black"))
-
+# Reset defaults by using `new = NULL`
+update_geom_defaults("point", NULL)
 
 # updating a stat's default aesthetic settings
 # example: change stat_bin()'s default y-axis to the density scale
@@ -42,7 +41,6 @@ ggplot(data.frame(x = rnorm(1e3)), aes(x)) +
   geom_function(fun = dnorm, color = "red")
 
 # reset default
-update_stat_defaults("bin", aes(y = after_stat(count)))
-
+update_stat_defaults("bin", NULL)
 }
 \keyword{internal}
diff --git a/tests/testthat/test-geom-.R b/tests/testthat/test-geom-.R
index 409aa19b8f..2529e8fed1 100644
--- a/tests/testthat/test-geom-.R
+++ b/tests/testthat/test-geom-.R
@@ -6,6 +6,21 @@ test_that("aesthetic checking in geom throws correct errors", {
   expect_snapshot_error(check_aesthetics(aes, 4))
 })
 
+test_that("geom defaults can be set and reset", {
+  l <- geom_point()
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "black")
+
+  inv <- update_geom_defaults("point", list(colour = "red"))
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "red")
+  expect_equal(inv$colour, "black")
+
+  inv <- update_geom_defaults("point", NULL)
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "black")
+  expect_equal(inv$colour, "red")
+})
 
 
 test_that("updating geom aesthetic defaults preserves class and order", {
@@ -23,13 +38,9 @@ test_that("updating geom aesthetic defaults preserves class and order", {
 
   expect_equal(updated_defaults, intended_defaults)
 
-  update_geom_defaults("point", original_defaults)
-
+  update_geom_defaults("point", NULL)
 })
 
-
-
-
 test_that("updating stat aesthetic defaults preserves class and order", {
 
   original_defaults <- StatBin$default_aes
@@ -46,6 +57,5 @@ test_that("updating stat aesthetic defaults preserves class and order", {
 
   expect_equal(updated_defaults, intended_defaults)
 
-  update_stat_defaults("bin", original_defaults)
-
+  update_stat_defaults("bin", NULL)
 })