The Black Eyed Peas frontman posted the snippet along with a note addressed directly to Spears: "Thank you Britney for collaborating it was a pleasure working with you. Thank you for trusting my instincts. You're a doll," will.i.am wrote.
"I did this little art my self on my Mac," he continued. "I made it on the plane from Japan to L.A....I hope your Britney army likes it as much as we do."
"The Big Fat Bass" is the fourth song to be teased from Britney Spears' "Femme Fatale" aside from its lead single, "Hold It Against Me," which debuted at No. 1 on the Billboard Hot 100. Last week, the pop star previewed three other tracks helmed by the album's co-executive producer, Dr. Luke: "Inside Out," "I Wanna Go," and "How I Roll."
Spears also announced last week that she'll perform a special concert on March 29, the same day "Femme Fatale" hits stores. The performance, which is set to take place in San Francisco, will be televised live on "Good Morning America."