Khali, who plays the young mechanic, is currently filming his final scenes after almost two years on the BBC One soap.
An EastEnders spokesperson told Daily Star on Sunday: "We can confirm that Khali Best will be written out of EastEnders before Christmas. We wish him all the best for the future."
Khali, who picked up a gong for 'Best Newcomer' at the National Television Awards earlier this year, said he has had an "amazing" two years and will now pursue new challenging roles.
Khali first appeared in EastEnders in January 2013, playing the grandson of Cora Cross and the son of Ava Hartman.
Viewers have seen Dexter involved in various storylines, including his friendship with Jay Brown and Lola Pearce, as well as his turbulent relationship with his estranged father, Sam, who tracked him down to ask him to donate a kidney.
In May this year, EastEnders confirmed that Khali had been suspended from the soap for three months.
Following his return, viewers watched Dexter attempt to pursue a romance with Nancy Carter.
News of Khali's departure comes as EastEnders confirmed the exit of two popular cast members. Ben Hardy, who plays Peter Beale, will leave at the end of his contract, while Sam Strike, who plays Johnny Carter, will also bow out of the soap.
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