Photo Credit: Patrick Stump/Twitter

Fall Out Boy is pulling out the big guns for their upcoming fifth studio album, Save Rock and Roll. One of the biggest guns ever, in fact: Sir Elton John.

Yesterday, FOB lead singer Patrick Stump tweeted the photo above with the mysterious caption, "#saverockandroll #sireltonjohn." Today, Fuse confirmed that the band have, in fact, tapped the singing and songwriting legend for work on the album. "They're currently working with Elton John on Save Rock and Roll in a studio in Atlanta [Elton's hometown]," a representative for the band said.

Elton John and Fall Out Boy? Kind of a crazy combo. What do you guys think? Let us know in the comments. And listen to Fall Out Boy's first Save Rock and Roll single, "My Songs Know What You Did in the Dark (Light Em' Up)," in the mean time...