Kone has arrived from Wigan Athletic in the last week.
"It makes them work harder, it makes them strive to improve themselves every single day. Jela turned up to watch us. He tried to keep it a secret and came as a surprise before travelling back with us. Then he'll be right back on it on his first day of training," Osman told the Liverpool Echo.
"He seems happy. I don't know whether it's because he's had a good summer or he's just happy to see us. He seems lively and raring to go."