Mats Hummels has lifted the lid on his temperamental relationship with Jurgen Klopp when the pair were together at Borussia Dortmund.
Hummels - now with Bayern Munich and representing Germany at Euro 2016 - worked under Klopp from 2008 until 2015, before the latter moved on to Liverpool, and things did not always run smoothly between them.
"You can always have a discussion with your coach and raise your voice," the defender told L'Equipe.
"It does not happen often with [Germany coach Joachim] Low, but things occasionally got very intense with Klopp. There was a lot of emotion. We had our fair share of quarrels.
"But things were all good again an hour later and we understood each other. We had a great relationship.
"I don't think I'm a difficult person. I'm just someone who can be an emotional person."
Hummels' switch from Dortmund to Bundesliga rivals Bayern attracted criticism from some BVB fans when it was announced in May.
The club still had two league games to go and a DFB-Pokal final against Bayern, which the Bavarians won on penalties.