diff --git a/docs/the_nimbus_book/src/options.md b/docs/the_nimbus_book/src/options.md
index b6842092b..8c998f7d6 100644
--- a/docs/the_nimbus_book/src/options.md
+++ b/docs/the_nimbus_book/src/options.md
@@ -33,6 +33,7 @@ The following options are available:
      --network                 The Eth2 network to join [=mainnet].
  -d, --data-dir                The directory where nimbus will store all blockchain data.
      --validators-dir          A directory containing validator keystores.
+     --validators-source       Remote Web3Signer URL that will be used as a source of validators.
      --secrets-dir             A directory containing validator keystore passwords.
      --wallets-dir             A directory containing wallet files.
      --web3-url                One or more execution layer Engine API URLs.