Glee will "deal directly with the incidents involved" in the death of Cory Monteith, says Kevin Reilly, chairman of entertainment at Fox.
Monteith played Finn Hudson, a high school sports star turned choir member.
The 31-year-old died last month in Vancouver, of an accidental overdose of heroin and alcohol.
The fifth series of the US TV show, due to start in September, has already been delayed by a week as writers rewrite episodes without Monteith's character.
"[The] third episode will deal with the Finn Hudson character being written out of the show," Reilly told reporters at a Television Critics Association meeting.
"I can't speak to it yet because [it's still being written]. That episode will deal directly with the incidents involved in Cory's passing and the drug abuse in particular," Reilly added.
Money from music sales for the tribute will go into a fund in Monteith's honour.
He also said that the cast will record public service announcements about drug abuse to air during the episode.
The series will now start on US television on 26 September and may be one of the programme's last.
"I would not anticipate it goes beyond two more seasons," he said.
Monteith was in a relationship with Glee co-star Lea Michele at the time of his death.
Earlier this week she told her 3.5 million followers on Twitter: "Thank you all for helping me through this time with your enormous love & support. Cory will forever be in my heart."
Monteith missed the filming of the final episodes of the fourth series of Glee after voluntarily checking into rehab for substance abuse in April.
The actor had been open about his battle against addiction and was first treated for drug abuse aged 19.
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