diff --git a/poky/meta/classes/externalsrc.bbclass b/poky/meta/classes/externalsrc.bbclass
index 54b08ad..7f1a760 100644
--- a/poky/meta/classes/externalsrc.bbclass
+++ b/poky/meta/classes/externalsrc.bbclass
@@ -110,6 +110,16 @@
                 continue
             bb.build.deltask(task, d)
 
+        if bb.data.inherits_class('reproducible_build', d) and 'do_unpack' in d.getVar("SRCTREECOVEREDTASKS").split():
+            # The reproducible_build's create_source_date_epoch_stamp function must
+            # be run after the source is available and before the
+            # do_deploy_source_date_epoch task.  In the normal case, it's attached
+            # to do_unpack as a postfuncs, but since we removed do_unpack (above)
+            # we need to move the function elsewhere.  The easiest thing to do is
+            # move it into the prefuncs of the do_deploy_source_date_epoch task.
+            # This is safe, as externalsrc runs with the source already unpacked.
+            d.prependVarFlag('do_deploy_source_date_epoch', 'prefuncs', 'create_source_date_epoch_stamp ')
+
         d.prependVarFlag('do_compile', 'prefuncs', "externalsrc_compile_prefunc ")
         d.prependVarFlag('do_configure', 'prefuncs', "externalsrc_configure_prefunc ")