Little House on the Prairie was filming in an old railroad car the day I went to see Melissa Sue Anderson. Melissa plays Mary Ingalls in the popular NBC series. The episode being filmed that day was about Mary. In a previous show, Mary had become engaged. Now the engagement was being broken. We stood and watched while the scene was done over several times. Then lunch break was called.

Melissa and her mother joined us for lunch in the commissary nearby. There wasn't time for Melissa to change her clothes, so she continued to wear the old-fashioned dress and high-button shoes. She looked down at the costume. She'd like to do another TV series someday, she said, but she hopes it won't be a Western set in the 1800's!

Melissa is a 10th-grade student at a girls' parochial school. "Some years 1 don't spend much time there, though," she said. "Last year 1 went there 19 days. When I'm working, 1 go and get my assignments and then have a tutor on the set. I take algebra, English, French, history - the usual courses. I usually get straight A's."

Melissa was born in Berkeley, California, on September 26, 1962. She began her show business career after her dancing teacher urged her parents to get an agent for her. They did, and Melissa soon began doing TV commercials. "The first commercial 1 did was for a toy company," Melissa recalled.

Her mother remembered the day she did that commercial. "I was terrified," she said. "I thought Melissa might not understand what the director was telling her to do. But we went in at 8:30 A.M. and Melissa was still laughing on cue at 5 P.M.!"

"Yes," Melissa interjected, "you do commercials over and over. Sometimes you shoot a 30second commercial more than 50 times! 1 liked doing that toy commercial," she added, "but my favorite commercial was one for French's Mustard. I did that on the beach. That was fun!"

Melissa lives with her mother and her dog, Barney, a lhasa apso. She has an older sister who is married and lives in northern California. She and her mother live in a condominium near the studio. "I have to help around the apartment," Melissa said. "I have to clean my room and my bathroom. I get an allowance, but I usually blow it all in one day. I spend it on anything!" She laughed, her blue eyes sparkling. "I buy clothes, tennis shoes, books. I like to read mysteries and 1 liked Rich Man, Poor Man and Once an Eagle. But I especially like to buy tennis shoes. I'm going to buy a new pair tomorrow!"

The day we had lunch, Melissa ordered a hamburger without the roll. "I want to lose five pounds," she confided. "I'm 5'4" and 1 weigh 103 now. 1 have to stay thin because you always look heavier on TV. 1 don't eat dinner. I eat breakfast and lunch. I'm on a liquid protein diet now. In the scene we were doing this morning, I was supposed to take a bite of a peanut butter sandwich. I didn't want to because of my diet, but I finally had to. That's why I'm not eating much lunch."

I asked Melissa what she liked to eat when she wasn't dieting. "I like caramels and Snickers candy bars," she answered quickly. "If I went on an eating binge, I'd have waffles floating with butter. No, swimming in butter! For lunch I'd have a cheeseburger. Then I'd buy a bag of little Milky Ways which I'd put in the freezer and munch on for dinner." She looked wistful as she thought about her dream diet.

"There are some things I don't like," she declared. "I hate licorice candy, brussel sprouts, vanilla milk shakes, hard candy, and chocolate eclairs."

Scratch the chocolate eclairs for dessert, I thought to myself. Melissa smiled. "I like peanut butter sandwiches," she added, "but I hope I don't have to eat too many of them this afternoon!"

Melissa, at 15, is an experienced actress. She's had one of the leading roles in Little House on the Prairie for three years now. Last spring, she also starred in an ABC Afterschool Special called Very Good Friends. It was the story of two young sisters, one of whom was accidentally killed in a fall from a tree. "I enjoyed doing that very much," said Melissa. "It was a good story. I was also in a TV film called James at 15. And I did an All-Star Anything Goes!"

When Melissa is working in Little House on the Prairie, she usually gets to the set about 8 A.M. "Then sometimes I get off at noon or I may work until 5 P.M.," she explained. "It depends on what scenes they are doing that day. When I get home, I lie out in the sun or I get together with my friends. I usually watch TV when I get home from work, too. It's relaxing; you don't have to think about it, you just sit and watch. I enjoy doing that. I usually watch about three programs. Then I quit, study my lines for the next day, and then go have a sauna. If I get home really early, I watch soap operas - but I don't really like them.

"I wash my hair every night," Melissa said. "And I exercise every day. I swim and do other exercises. I do sit-ups. I dry my hair while I'm exercising. I do donkey kicks - that's when you're on your hands and knees and kick out and hip rolls. I used to curl my hair, but I don't anymore. Everybody else with long hair is keeping it straight, so I decided to do that, too. When I'm not working, I wear blue jeans most of the time." She smiled, looking again at the costume she has worn so regularly for the past three years.

Melissa said that Michael Landon, who plays Pa Ingalls on the series, has been the most helpful to her in her career. "I've learned everything from him," she raved. "He is a super person. I have never met anyone like him. He writes and directs and does everything! Someday I'd like to direct TV shows. I've learned a lot just from watching him.

"I've never had any acting lessons," Melissa said. "I've learned from watching others and from playing this part. I usually spend five to ten minutes a day learning my lines. I go over them at night just before my head hits the pillow. Then, if I'm lucky, the words just flow out of my mouth the next day! I think the hardest thing to do," she added, "is to react. Saying the words isn't hard, but reacting can be!"

Melissa's best friends are two twin girls. "Tomorrow," she explained, "I'm going to have a tennis lesson. Then my friends will pick me up and we'll go to their house and work on my fan mail. They started my fan club. I sign the pictures and stuff the envelopes. They type the addresses and so on. We get a lot of mail, but we try to keep up with it. It takes a lot of time to open it and read it. When we're not doing that we go to movies. I like movies, although I used to go to them more than I do now."

Melissa tries not to let her work interfere too much with her private life. "Once we leave the studio," she told me, "we try to leave 'show business' behind. Our friends - or most of them, at least - are not in the business."

Melissa's mother spends each day on the set with her daughter. "She must have someone with her because she is underage," she explained, "and I think it's important for me to be there. I sit off at the side and pay bills, do crocheting, needlepoint, etc. One thing I have always demanded from both my daughters," she added, "is respect. I think that's one thing that's missing today."

Does Melissa get tired of playing the same role? She smiled at the question. "I get tired of it sometimes," she answered, "but mostly I enjoy it. And it's nice to know that you have a job. It's like having a teddy bear - it's something steady you can depend on!".

What does this successful young actress hope to do in the future? "Keep on acting," she replied even if it means wearing old-fashioned dresses and bonnets instead of the blue jeans she prefers!