Authorities in Los Angeles are seeking the public's help in the search for a 20th Century Fox distribution executive and former UCLA basketball player, Gavin Smith, who disappeared last week.

Smith, 57, was reported missing by his wife on Wednesday morning. According to authorities, he was last seen driving away from a friend's home in Oak Park, California.  Family members haven't heard from him since, and his sister says Smith would never have abandoned his family.

"My biggest concern is that he did not pick up his son, which he was supposed to pick up on Wednesday morning to take him to school, and that is a concern for me," said Tara Addeo, Smith's sister told KABC-TV.

Los Angeles County Sheriff Public Information Officer Steve Whitmore told ABC News it's an active missing-person case and ongoing investigation.

Authorities say he was driving his black 2000 Mercedes-Benz 420E with a storage rack on the roof, tinted windows and a California license plate number 6EKT044. Evan Smith, a forward for the University of Southern California basketball team and Gavin's son, has been using Twitter to spread the word on his father's disappearance.

"Still looking for him, I'll never stop," Evan Smith tweeted on Sunday.

Today he tweeted, "WOW. So many people have come to my family's side in these times of despair and confusion. i thank each and everyone of you for your support."

Gavin Smith played for UCLA's 1975 national championship team under the legendary coach John Wooden. He has been a longtime employee at Fox.

Chris Aronson of 20th Century Fox said in statement that they are "extremely worried" about Smith and they are actively assisting the sheriff's search for him.

Gavin Smith is described as 6 feet 6 inches tall, weighing 210 pounds, with green eyes, gray hair with blond streaks and a goatee. He has a 5-inch scar on his calf and a 4-inch scar on his inner right wrist.

Anyone with information about Smith's whereabouts is urged to contact detectives at the Los Angeles County Sheriff's Department's Homicide Bureau.