Missy Elliott
Missy Elliott, pictured here performing at the Alexander Wang X H&M Launch on in New York City Oct. 16, 2014, said she worked on music the entire time she was on a 10-year hiatus. Getty

After a decade out of the spotlight, musician Missy Elliott is back and ready to "get her freak on." Last week, Elliott dropped her first new song in 10 years with "WTF (Where They From)", which features Pharrell Williams.

In an interview with Billboard, the "Work It" rapper discussed what lead to her hiatus, citing health problems, which she says was a result of her busy schedule. Elliot had to battle Graves' disease, an autoimmune disorder that affects the thyroid. She noticed she had a problem when she began losing a lot of weight in 2008.

"It causes hair loss, your eyes bulge,” Elliott said. “My blood pressure was always up from just overworking."

Although the 44-year-old performer hasn't done much publicly since 2005, she says she never stopped working over the past 10 years. Her break lasted longer than she expected, but she helped other artists make music in her time away, while also writing her own music that she hasn't yet released.

"If I wanted to do The Missing Files of Missy Elliott, I have probably six albums just sitting there," she dished."People hadn’t realized that I haven’t just been an artist, I’ve been a writer and a producer for other artists. When you’re writing that much, your brain is like a computer. You have refresh it."

The "Gossip Folks" singer returned to the public eye in February when she made a surprise appearance alongside Katy Perry during the Super Bowl XLIX Halftime Show. Elliott performed three songs, including her hits “Lose Control” (2005) “Get Ur Freak On” (2001) and “Work It” (2002). Elliott told Billboard Perry's team called her about the idea of making a cameo and then Perry called herself to say she wanted Elliott to perform three songs.

Watch Elliott's Super Bowl performance below:

Elliott is expected to release a new album in 2016 and also hopes to tour. Until then, fans have the single "WTF (Where They From)" to hold them over. Elliott will also be given the inaugural Innovator Award at the 2015 Billboard Women in Music ceremony for her work in pop music. Her last release was 2005's "The Cookbook," which debuted at No. 2 on the Billboard 200 and went on to be certified Gold after it sold more than 645,000 copies in the U.S.

Watch the music video for "WTF (Where They From)" below: