The 21-year-old was one of three players drafted into the senior set-up on Sunday after James Maddison, Callum Wilson and Lewis Dunk withdrew through injury.
The call-up came hours after Palmer kept his cool from the penalty spot in the dying moments of Sunday's clash chaotic 4-4 draw with former club Manchester City.
It was Palmer's fourth goal for the Blues since his arrival from the Treble winners on a seven-year contract.
The Chelsea midfielder, who joined up with the rest of the England squad at St. Georges Park on Monday, is in line to make his debut in Friday night's clash with Malta at Wembley.
Should Palmer not feature on Friday, he could get another opportunity when the Three Lions travel to North Macedonia on Monday.
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England's social media account shared a clip of Palmer reporting for international duty, only to be greeted by a shocked and surprised Chelsea teammate Conor Gallagher.
Gallagher amazingly then turns to Palmer and says: "Congrats to you, didn't realise you'd been called up!"
"Yeah, right after the game it was," Palmer replied before adding: "I thought it was a blag at first. I swear. It looked real, so…"
The clip was posted on England social media account accompanied with a laughing emoji and the caption: "Definitely real, Cole"
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Palmer has quickly become a fan-favourite at Stamford Bridge and further endeared himself to the Chelsea faithful following his last-gasp heroics against City.
The £42.5million summer signing even managed a laid-back celebration shortly after dispatching his spot kick past former teammate Ederson.