Gunners boss Arsene Wenger makes 11 changes for the trip to the Madejski Stadium and includes youngsters Serge Gnabry and Ignasi Miquel as well as other fringe players
Moroccan striker Chamakh is included from the start for the first time since the Gunners saw off Leeds in the FA Cup third round in January, while Walcott makes his first start for five weeks due to contract issues and after sustaining a chest injury.
Johan Djourou captains the Gunners, while Carl Jenkinson is also recalled to the starting XI after being dropped for the returning Bacary Sagna on Saturday.
Emmanuel Frimpong makes his first start of the season after recovering from a knee ligament injury and youngster Serge Gnabry is offered the chance to further stake a claim for a first-team spot.
Reading, meanwhile, make six changes from the team that secured a thrilling 3-3 draw with Fulham at the weekend as boss Brian McDermott looks to freshen up the Royals side.
Adam Federici comes in for Alex McCarthy having been dropped for a number of early-season errors while captain Jobi McAnuff drops to the bench as Hal Robson-Kanu takes his place on the left.
Chris Gunter, Sean Morrison, Garath McCleary and Noel Hunt also come in for Shaun Cummings, Adrian Mariappa, Jimmy Kebe and Pavel Pogrebnyak respectively.
Reading: Federici; Gunter, Gorkss, Morrison, Shorey; McCleary, Leigertwood, Tabb, Robson-Kanu; Hunt, Roberts
Subs: Taylor, Harte, Pearce, McAnuff, Church, Le Fondre, Pogrebnyak
Arsenal: Martinez; Jenkinson, Djourou, Miquel, Koscielny; Frimpong, Coquelin; Walcott, Arshavin, Gnabry; Chamakh
Subs: Shea, Yennaris, Squillaci, Bellerin, Eisfeld, Meade, Giroud