diff --git a/platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_TFM_LATEST/TARGET_TFM_V8M/src/tfm_mbed_boot.c b/platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_TFM_LATEST/TARGET_TFM_V8M/src/tfm_mbed_boot.c
index 87bcbbbf66d..6016a2ec465 100644
--- a/platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_TFM_LATEST/TARGET_TFM_V8M/src/tfm_mbed_boot.c
+++ b/platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_TFM_LATEST/TARGET_TFM_V8M/src/tfm_mbed_boot.c
@@ -18,6 +18,8 @@
 #include "mbed_error.h"
 #include "tfm_ns_interface.h"
 
+int32_t tfm_ns_interface_init(void);
+
 void mbed_tfm_init(void)
 {
     /*