Tracy Morgan remains in critical condition as he recovers from a fatal weekend crash. James McNair, a comedy writer and friend of Tracy's, was killed when their limo was struck by a Walmart truck.  Morgan broke several bones, has undergone surgery and is expected to be hospitalized for weeks. See footage from right after the crash.

Tracy's rep says: 'While Tracy remains in critical condition, he has been more responsive today, which is an incredibly encouraging sign. He had surgery earlier today on his leg. We expect him to remain in the hospital for several weeks. His family is tremendously overwhelmed and appreciative of the outpouring of love and support from his fans.'

The Walmart truck driver, Kevin Roper turned himself in and is charged with death by auto and assault by auto, according to NBC 10 in Philadelphia.

Walmart President/CEO Bill Simon says they will step in and help. 'This is a tragedy and we are profoundly sorry that one of our trucks was involved. We can't change what happened, but we will do what's right for the family of the victim and the survivors in the days and weeks ahead.'

Celebrities and fellow comedians are sending their thoughts and prayers on Twitter.