The actor is a diehard Hammers fan and a regular attendee at the London Stadium, while his interest in the club has only ramped up in the wake of the relationship between Dyer's daughter Dani and forward Jarrod Bowen.
Last week, Dyer recorded a welcome voice note for Lopetegui as part of Sky Sport's 'messages of hope' for all 92 EFL clubs ahead of the start of the 2024-25 season.
Dyer was keen to let the new head coach in on the heady expectations of the fans via Sky Sport's campaign, telling 'Jules' that he was looking for his team's players to 'die for their shirt'.
He also made sure to mention his son-in-law to-be, saying that Lopetegui had been 'blessed with' Bowen in his squad.
Julen Lopetegui was seen watching the clip that was shared on social media last week
'What a player,' Dyer continued. 'What a man. The team needs to be build around him. I love you Jules. Don't let me down. God bless ya.'
And Lopetegui has now responded with a message of his own for the actor., saying they'll both have to work together to get the best out of Bowen.
Sky Sports shared a video of the Spaniard watching Dyer record the message, writing: 'yes, Hammers fans... new boss Julen Lopetegui has actually seen Danny Dyer's message ahead of the new season, AND he's issued a response.'
'I love you too! Danny, for sure, and you and me, both, we are responsible about Jarrod's performance,' he said.
'Depends on your daughter! So I have to push Jarrod and you have to push your daughter. Are you agreeing with me? Come on!'
Lopetegui joined the club in May following the departure of Moyes and has since embarked on an efficient spending spree during the summer transfer window.
The Hammers kick off their campaign at home to Aston Villa on Saturday evening.