updated 08/04/2011 AT 2:00 PM ET
•originally published 08/04/2011 AT 2:25 PM ET
Now, the 21-year-old singer will be joining his childhood crush on her European tour starting Oct. 16, he tells PEOPLE.
“It’s a dream come true,” says Jonas, who will be opening for Spears and promoting his upcoming solo album Fastlife, to be released Oct. 11.
“She was the first girl I ever had a poster on my wall of, and her album was the first CD I ever bought,” says Jonas. “It’s so funny to think I had that on my wall and here I am about to perform with her.”