Taking to Twitter following Monday night's instalment, the actor, who plays DI Sunny Khan in the drama, shared some behind-the-scenes trivia with his followers.
The star explained that when Sunny's phone call with his wife Sal cut out whilst going through the Eurostar on his way to Paris, the shoot only took one take because Sanjeev lost phone signal in real life!
WATCH: Unforgotten series five scene that happened in real life
"So BTS trivia moment from Ep 3 S5 of @UnforgottenTV," he told his 119k followers. "The scene where Sunny phones Sal from the Eurostar- the signal is lost going into a tunnel - it was just one take, as, by sheer fluke, at the exact moment, we actually went into a tunnel! It would’ve been impossible to time it."
Fans were quick to praise the series in the comments section, with one person writing: "Brilliant, so love this series," while another added: "Great trivia. Fabulous performance."
Sanjeev revealed that his phone signal cut out in real life during filming
It's safe to say fans are certainly enjoying the new series, which sees DI Sunny and his new boss DCI Jessie James (played by Sinéad Keenan) look into the mysterious discovery of human remains in a newly restored period home in Hammersmith, London.
Viewers who have yet to binge-watch the entire series on ITVX have already taken to Twitter to share their predictions on the twist ending.
Sanjeev stars opposite new addition to the cast Sinéad Keenan
In episode one, Jessie learnt of her husband's affair - and fans are convinced they know who the other woman is. "Catching up on #unforgotten and wondering if the new DCI's husband was having it off with her sister," wrote one fan. A second agreed, adding: "What's the betting the husband had an affair with the sister."
For those who have already watched all six episodes, read our explainer on the dramatic final episode here.
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