diff --git a/src/Client.js b/src/Client.js
index d59bac6..d5eb7b7 100644
--- a/src/Client.js
+++ b/src/Client.js
@@ -742,6 +742,10 @@ class Client extends EventEmitter {
      * @returns {Promise<Message>} Message that was just sent
      */
     async sendMessage(chatId, content, options = {}) {
+        if (options.mentions && options.mentions.some(possiblyContact => possiblyContact instanceof Contact)) {
+            console.warn('Mentions with an array of Contact are now deprecated. See more at https://github.com/pedroslopez/whatsapp-web.js/pull/2166.');
+            options.mentions = options.mentions.map(a => a.id._serialized);
+        }
         let internalOptions = {
             linkPreview: options.linkPreview === false ? undefined : true,
             sendAudioAsVoice: options.sendAudioAsVoice,
@@ -751,7 +755,7 @@ class Client extends EventEmitter {
             caption: options.caption,
             quotedMessageId: options.quotedMessageId,
             parseVCards: options.parseVCards === false ? false : true,
-            mentionedJidList: Array.isArray(options.mentions) ? options.mentions.map(contact => contact.id._serialized) : [],
+            mentionedJidList: Array.isArray(options.mentions) ? options.mentions : [],
             extraOptions: options.extra
         };