The Belgium international, like Lukaku, began his career with the Brussels giants before making waves at the top level of European football.
While still a youth player, a 15-year-old Doku attracted the interest of a number of Premier League clubs, including Chelsea.
As such, the Belgian club were struggling to convince the winger to stay, only for Lukaku to step in.
Having gone on a similar journey but to then have found first-team opportunities initially limited at Stamford Bridge before moving on to Everton where he truly launched his career, the striker offered his compatriot some words of advice.
“I remember taking Romelu into my office about the problem of getting young players to commit to us – Doku in particular,” Kindermans told the Sunday Mirror.
“Romelu replied, ‘Come on, pass your phone to me, I’m going to call him’.
“But I didn’t want to do that because a phone call gets quickly forgotten. So, instead, I got Romelu to convince Jeremy to stay.
“I still have the video on my phone. On it, you can hear Romelu giving advice to the Doku family, saying ‘Hey, guys, stay with Anderlecht for a while, you’re good’ and so on.”
Doku eventually made his first-team debut in 2018 at the age of 16 and earned a move to Rennes two years later before signing for City in a deal thought to be worth in the region of £55.5m.
Lukaku, meanwhile, has since returned to Chelsea and subsequently left on two occasions, spending last season on loan with Inter Milan before joining Roma on a similar deal last month.