"When he decided to go to Leverkusen he called me," said Bilic.
"He was very polite. He told me 'coach, sorry but I opted for Leverkusen'. It was a really nice gesture from him.
"Now, after two years, when we found out he might leave Leverkusen I called him again and of course we didn't have to start from zero.
"We were laughing and he said 'we spoke two years ago' and all that, so it probably helped that he knew that we wanted him."