The 30-year-old actress shared her debut public message earlier this week while getting ready for an appearance at the Met Ball Costume Institute Gala 2012, reported Contactmusic.
Biel has acquired approximately 19,000 followers in two days.
Despite her immediate popularity on the micro-blogging website, she has subscribed to three accounts, including that of her fiance Justin Timberlake, 31.
Biel and Timberlake attended Monday's party with the actress proudly displaying her new engagement ring.
The couple is reportedly planning to marry this summer.
"They definitely seemed fond of each other. They were extremely personable, comfortable and relaxed. They weren't holding hands or anything, but they just seemed comfortable with each other," a source said.