Lassie (TV series)
The show had a large cast over the years. Tommy Rettig played the farm boy for the first three years. Jon Provost became the farm boy in 1957 when Rettig left the show.  Jan Clayton played Rettig's mother and June Lockhart played Provost's. Hugh Reilly played Provost's father. Both actresses were nominated for Emmys. The show had its best ratings during the Provost years of the early 1960s. Some episodes from these years were put together to make a color adventure movie for theatres.