Of course! Depending on the platform you're playing from (Lazyland, Facebook, iOS, Android, Zoo, etc.), just click on "Invite friends" that appears on the far-left side of your screen if you play via a PC, or on "Play with a Friend" if you are connecting via an iOS or Android device.
You will see a window where you get a link by clicking "Invite". Just send the link in whatever way you want to your friend (e.g. if your friend is online on Facebook chat or Skype you can send it there). When your friend clicks the link, he will enter the game and you can start playing together. It's that simple!