Although filming doesn't actually begin until later this month on the recently retitled G.I. Joe 2: Retaliation, star Dwayne Johnson, aka The Rock, is already hard at work on the sequel to 2009's G.I. Joe: The Rise of Cobra. How do we know? Because Johnson has tweeted photos of himself as Roadblock holding his weapon, and striking a pose at NASA before combat training.

"Found my gun today! M249 SAW," Johnson tweeted with the first photo. Slipping into his Rock persona, Johnson asked "Guess who/what I envision in my crosshairs," a veiled "threat" directed toward WWE superstar John Cena. Johnson has been utilizing the social media platform since April to promote the promised WrestleMania 28 clash between the two superstars in April, 2012.

Directed by Jon M. Chu, G.I. Joe 2: Retaliation also stars Channing Tatum, Adrianne Palicki, Ray Stevenson, Ray Park and Byung-hun Lee. It opens on June 29, 2012.