diff --git a/R/html_add_header_above.R b/R/html_add_header_above.R
index 3acb2e1..c9b153e 100644
--- a/R/html_add_header_above.R
+++ b/R/html_add_header_above.R
@@ -1,16 +1,51 @@
 #' Add an extra header row above the current header
 #' @export
 htmlTable_add_header_above <- function(kable_input, header = NULL) {
-  if (is.null(header)) return(kable_input)
+  # if (is.null(header)) return(kable_input)
   kable_xml <- read_xml(as.character(kable_input), options = c("COMPACT"))
-  kable_xml_thead <- xml_child(kable_xml, "thead")
+  # somehow xml2 cannot directly search by name here (it will result in a crash)
+  kable_xml_thead <- xml_child(kable_xml, 1)
+  if (xml_name(kable_xml_thead) != "thead") {
+    kable_xml_thead <- xml_child(kable_xml, 2)
+  }
 
+  header <- standardize_header_input(header)
 
-  x <- read_xml("<parent><child>1</child><child>2<child>3</child></child></parent>")
-  children <- xml_children(x)
-  t1 <- children[[1]]
-  t2 <- children[[2]]
-  t3 <- xml_children(children[[2]])[[1]]
+  header_rows <- xml_children(kable_xml_thead)
+  bottom_header_row <- header_rows[[length(header_rows)]]
+  kable_ncol <- length(xml_children(bottom_header_row))
+  if (sum(header$colspan) != kable_ncol) {
+    stop("The new header row you provided has a different total number of ",
+         "columns with the original kable output.")
+  }
 
+  new_header_row <- new_header_generator(header)
+  xml_add_child(kable_xml_thead, new_header_row, .where = 0)
+  return(structure(as.character(kable_xml), format = "html",
+                   class = "knitr_kable"))
+}
 
+standardize_header_input <- function(header) {
+  header_names <- names(header)
+
+  if (is.null(header_names)) {
+    return(data.frame(header = header, colspan = 1, row.names = NULL))
+  }
+
+  names(header)[header_names == ""] <- header[header_names == ""]
+  header[header_names == ""] <- 1
+  header_names <- names(header)
+  header <- as.numeric(header)
+  names(header) <- header_names
+  return(data.frame(header = names(header), colspan = header, row.names = NULL))
+}
+
+new_header_generator <- function(header_vector) {
+  header_items <- apply(header_vector, 1, function(x) {
+    paste0('<th style="text-align:center;" colspan="', x[2], '">',
+           x[1], '</th>')
+  })
+  header_text <- paste(c("<tr>", header_items, "</tr>"), collapse = "")
+  header_xml <- read_xml(header_text, options = c("COMPACT"))
+  return(header_xml)
 }
diff --git a/R/kableExtra-package.R b/R/kableExtra-package.R
index cd0bbe8..6f7fa7e 100644
--- a/R/kableExtra-package.R
+++ b/R/kableExtra-package.R
@@ -2,6 +2,7 @@
 #'
 #' @importFrom stringr str_count
 #' @importFrom xml2 read_xml xml_attr xml_has_attr xml_attr<- read_html
+#' xml_child xml_children xml_name xml_add_sibling xml_add_child
 #' @importFrom rvest html_table
 #' @importFrom knitr kable
 #' @name kableExtra-package