For the first time since 1955, there...

For the first time since 1955, there is no Christmas show from Lawrence Welk this year. But he’ll be seen on PBS in the spring in “Lawrence Welk: Television’s Music Man.” It’s an hourlong retrospective featuring clips from his long-running TV series and interviews with him and some of his performers. Kathy Lennon will host the program.

John Davidson has been added to KTTV Channel 11’s telecast plans for this year’s Tournament of Roses Parade in Pasadena. He’ll co-host the station’s coverage along with parade veterans Bill Welsh and Mary Hart. . . . Meanwhile, KMEX Channel 34 reports that its Spanish-language telecast of the parade will be seen in at least 11 countries in Central and South America.

Michelle Phillips has been added to the cast of “Knots Landing.” She’ll turn up in January as the mother of Paige (Nicollette Sheridan). Phillips, who first gained fame as a singer with the Mamas and the Papas, appeared earlier this season on ABC’s “Hotel.”

David Mamet, the Pulitzer Prize-winning writer of “Glengarry Glen Ross,” “American Buffalo” and “Sexual Perversity in Chicago,” has written a script for NBC’s “Hill Street Blues.” The show, to be telecast Dec. 30, features a role for his wife, Lindsay Crouse, reprising her character of Officer McBride.

Last season CBS broadcast a TV movie about a pair of doctors who had alcohol and drug dependency problems; now it’s doing one about a nurse with the same problem. Cheryl Ladd stars in “One Way Out,” with Jason Miller as a surgeon and Jennifer Salt as a friend.