Tsimikas, 26, recently returned to Liverpool after representing his country in their Nations League games against Cyprus and Northern Ireland earlier this month.
The 26-year-old was sporting a slightly longer hairstyle than usual, which was tied up into a 'man bun' – not dissimilar to that of his new teammate Nunez.
And Klopp was quick to pick up on the similarity when Tsimikas reported back for club duty.
The first few minutes of Liverpool's 'Inside Training' video released this week is mainly Klopp ridiculing the defender for his new hairstyle.
"A good day and now this," Klopp joked, after seeing Tsimikas for the first time.
"No really! How much so I can cut it off?"
Tsimikas is fortunately able to laugh it off before Klopp returns with another attempt at winding up the left-back.
"At first I thought Darwin had shrunk," added Klopp, which drew another laugh from Tsimikas and several of his teammates.
Later on in the video, Virgil van Dijk tells Tsimikas "Kosti, he can't say that to you brother" - presumably referring to Klopp.
The Greek defender then approaches Mohamed Salah and Trent Alexander-Arnold for reassurance that he doesn't look like Nunez.
"It looks a bit like Darwin…," replies Alexander-Arnold.
Before Salah turns to face the camera, and adds: "Does he look like Darwin? He does!"
Spirits are clearly high at Liverpool as they prepare to return to Premier League action this weekend.
Klopp's side host Brighton on Saturday before Scottish Premiership side Rangers visit Anfield in the Champions League on Tuesday night.
Featured Image Credit: Liverpool FC & TikTok/Kklopptok
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