Rockers Linkin Park heads east next month to play a free concert in Moscow’s Red Square to promote Michael Bay’s 3D movie “Transformers: Dark of the Moon.”Pic opens the Moscow Film Festival on June 23, and that evening Linkin Park will play the Vasilyevsky Spusk outdoor concert arena with the Kremlin and multi-colored onion domes of St. Basil’s Cathedral as a backdrop. Linkin Park will perform several of its hits, including “Iridescent,” which is the end title song in the movie, the third of the “Transformers” films. Bay and “Transformers” stars are due to be at the gig to push the movie, which rolls out worldwide from June 29. Linkin Park’s “What I’ve Done” and “New Divide” featured in the previous “Transformers” films. The Moscow show, produced by Live Nation, takes place during the band’s European tour that begins June 11 in Austria, with shows scheduled for the U.K., Germany, Sweden, Norway, Finland, France, Switzerland, Italy and Belgium.