Toto Wolff has revealed that he remains in "regular contact" with F1 legend Niki Lauda.
Together, the duo own and run F1's highly successful works Mercedes team and several weeks ago, team chairman Lauda had a life-saving lung transplant.
The 69-year-old continues to recover in a Vienna hospital, and Mercedes boss Wolff says that "everyone" at the team misses him.
"For me I especially miss him from the human point of view. As a travel companion, a sparring partner and a friend," Wolff told Die Welt newspaper.
"It was important that we always had dinner in the evening to discuss the day - just the two of us. At the moment I have lost a very important contact person or opposite pole.
"His health is the most important thing for now, so he needs rest, but I'm in regular contact with him. He watches all the races and I try to keep him up to date as much as possible."
Lauda is a three-time F1 champion, winning the 1975, 1977 and 1984 championships.