Justin Bieber had a long Halloween chat with Jay Leno last night on the Tonight Show.

Justin chatted about his new Bat mobile, renting out the Staples Center for a romantic dinner with his girl, his new fragrance, and his favorite Halloween costume.

On his Christmas duet with Mariah Carey, “She’s super cool, It was cool because I got to do All I Want To For Christmas is You.”

The song appears on Justin’s first Christmas album, Under The Mistletoe, which is out today.

What was it like working with Carey? “It was tricky. She has super high notes, and it wasn’t like she was going to change the key for me, so I had to go in and do her key,” Justin explained.

The Biebs has surpassed two billion views on his official YouTube channel. In case you were wondering if the singer is descending in popularity, last month, he put up ninety-four million.