The veteran metal group recently confirmed that they have recruited Angra guitarist Kiko Loureiro into the band and that Lamb of God's Chris Adler would be playing drums on the new album.

Mustaine took to his Twitter account on Monday to update fans on the progress they made on the new music. He tweeted, "We're done writing and start tracking drums next. I am so excited! #Megadeth15"

On Tuesday he posted another message. He wrote, "I'm stoked so many people have reacted so positively about Kiko and Chris playing on this next record! Falling Upward again!"

Then yesterday (April 7th) he posted, "15 songs finished being written. Just waiting for Jr. to arrive. He is gonna freak over Chris and Kiko. #Megadeth15".