diff --git a/crates/matrix-sdk-crypto/src/olm/account.rs b/crates/matrix-sdk-crypto/src/olm/account.rs
index c3a2765ea..8eb52770d 100644
--- a/crates/matrix-sdk-crypto/src/olm/account.rs
+++ b/crates/matrix-sdk-crypto/src/olm/account.rs
@@ -819,7 +819,8 @@ impl ReadOnlyAccount {
     ) -> Result<SignatureUploadRequest, SignatureError> {
         let public_key =
             master_key.get_first_key().ok_or(SignatureError::MissingSigningKey)?.to_string();
-        let mut cross_signing_key = master_key.into();
+        let mut cross_signing_key: CrossSigningKey = master_key.into();
+        cross_signing_key.signatures.clear();
         self.sign_cross_signing_key(&mut cross_signing_key).await?;
 
         let mut signed_keys = BTreeMap::new();