The 25-year old will partner Tatiana Calderon for the final two rounds at Sochi, Russia and Yas Marina, Abu Dhabi.
Markelov made his debut in Formula 2 – then GP2 Series - back in 2014 and has contested five full seasons since, with nine race victories and a further eight podium finishes to his record.
He finished as Vice-Champion in 2017 to Charles Leclerc, and most recently competed earlier this season at Monte-Carlo, claiming a brace of top-six finishes.
Markelov will run with #22 – #19 has been retired for the rest of the season as a mark of respect for Anthoine Hubert.
The Championship resumes at Sochi Autodrom – Markelov’s home event – on 28-29 September.
Kenny Kirwan – BWT Arden Team Manager:
“Following on from recent tragic events and our return to Sochi as a two-car team, we are proud and humbled to have Artem join us for the remaining races of the season.
“Artem is a proven race winner in this category and we very much relish the opportunity to work together and to continue where we left off with Anthoine, who we miss very dearly.”
Artem Markelov (#22) said:
“First of all, I want to give my best to the family of Anthoine.
“This guy was not only a good driver, he was a great man who was happy all the time and always gave us a smile. He showed everyone his talent.
“Thanks to the team for trusting me in this situation and I’m going do my best for them. We are going to drive together in memory of Anthoine.
“I’m really happy I’ll be driving for BWT Arden for the rest of the championship.
“It’s a really nice opportunity to drive at my home Grand Prix again. I hope for a strong result and I’ll work hard to achieve it.”