Upon joining the Bundesliga giants from domestic rivals Borussia Dortmund in July 2014, it was well documented that the Poland international and the Dutch winger had their differences.
The attacking duo were seen arguing with each other on numerous occasions on the field due to their contrasting styles of play, but now the 28-year-old claims his connection with the former Real Madrid man is telepathic.
"Things were a bit difficult between me and Robben at first," he told AD. "I had to get used to him, I have to be honest about that.
"Our styles of play were very different, things were just not completely right. But look at how things are now.
"We only need to look at each other one second to know what the other is going to do. That is an amazing feeling on the pitch. He knows what I want and the other way around.
"Arjen is a great player and a very nice guy."