diff --git a/zircon/kernel/arch/arm64/hypervisor/BUILD.gn b/zircon/kernel/arch/arm64/hypervisor/BUILD.gn
index 024e8f3..515e79d 100644
--- a/zircon/kernel/arch/arm64/hypervisor/BUILD.gn
+++ b/zircon/kernel/arch/arm64/hypervisor/BUILD.gn
@@ -23,6 +23,7 @@
     "//zircon/kernel/dev/psci",
     "//zircon/kernel/dev/timer/arm_generic",
     "//zircon/kernel/hypervisor:headers",
+    "//zircon/kernel/lib/init",
     "//zircon/kernel/lib/ktl",
     "//zircon/kernel/lib/ktrace",
     "//zircon/system/ulib/affine",
diff --git a/zircon/kernel/arch/arm64/hypervisor/el2_cpu_state.cc b/zircon/kernel/arch/arm64/hypervisor/el2_cpu_state.cc
index f8a8e91..e4a35a8 100644
--- a/zircon/kernel/arch/arm64/hypervisor/el2_cpu_state.cc
+++ b/zircon/kernel/arch/arm64/hypervisor/el2_cpu_state.cc
@@ -12,6 +12,7 @@
 #include <kernel/cpu.h>
 #include <kernel/mutex.h>
 #include <ktl/move.h>
+#include <lk/init.h>
 #include <vm/physmap.h>
 #include <vm/pmm.h>
 
@@ -147,3 +148,13 @@
   }
   return ZX_OK;
 }
+
+LK_INIT_HOOK(
+    hypervisor_el2_state,
+    [](unsigned int) {
+      // Work around fxbug.dev/78920 by initialising the Mutex during boot.
+      //
+      // TODO(fxbug.dev/78920): Remove this once singleton mutexes are thread-safe on first use.
+      GuestMutex::Get();
+    },
+    LK_INIT_LEVEL_ARCH)