I am trying to make a promise function repeatedly call itself after interval

The promise function:

function bd() {
  return new Promise((resolve, reject) => {
        // gets message_bd
        resolve(message_bd)     
    })
  }

I try to call it repeatedly every 3 seconds like so:

var interval = setInterval(function(){
    bd().then((message_bd) => {
      console.log(message_bd)
  },3000);

the bd() gets called after the first 3 seconds and the message_bd gets resolved (everything's working), but then I get this error as the second 3 seconds finish:

 bd().then((message_bd) => {
    ^

TypeError: bd is not a function

Would appreciate any help :)