"Spy Kids" star Alexa Vega is a kid no longer ... and has the revealing new role to prove it!
The now-23-year-old actress recently posted a very sexy photo on her Twitter page, showing her stripped down to a metallic bra for her role in "Machete Kills."
Vega, who just got divorced from her 36-year-old husband Sean Covel, will play KillJoy in the flick -- an assassin who works for Sofia Vergara's character.
Click here to see out more pics from the "Machete Kills" set here -- and check out the gallery above to see how other former child stars have grown up!