It was only five weeks ago that Author and Actress Kay Thompson laid eyes on 7-year old Evelyn Rudie. Yet it was a year ago that she finished her book, "Eloise." And Evelyn, as anyone will see who looks in on the Playhouse 90 show Thursday at 9:30 p.m. KNXT (2) is "Eloise" right out of the book.

"I knew it the first time I saw her picture," Kay explained as we lunched near CBS Television City. Evelyn was busy finishing the first basket of crackers put in front of her by the overwhelmed waiter.

Flew to East
"We had already looked at more than 100 of Hollywood's top child actresses before coming across Evelyn's photo. I called her mother and asked if I could take the child for a ride. We planned to drive around the block for a few minutes but Evelyn kept me in stitches and we didn't get home until after dark."

Since then the two, Kay and Evelyn have been inseparable. Accompanied by the youngsters' parents, Mr. And Mrs. Emery Bernauer, they flew to New York to give eastern TV writers a chance for interviews and to acquaint the youngster with the Plaza Hotel, where all the action in the television show takes place.

"We had a party," Evelyn (or Eloise) told me innocently: "I served birdseed, dog biscuits and rubber chocolate candies. Everyone seemed to enjoy them."

Kay nodded approval. She was probably visualizing a new book on "Eloise." Besides her Plaza Hotel composition, in which she is ably backed by the sketches of Hilary Knight, she has collaborated with the artist on a new venture, "Eloise in Paris." There's just no place Kay won't take her new-found friend in the interest of good clean fun.

High IQ
Meanwhile Papa Bernauer was anxiously watching his offspring. He publishes education books but admitted "Eloise" didn't fall into his category.

"Evelyn has a very high IQ," he offered. It was the understatement of the lunch. "She's in the second grade at Gardner Street School but everyone tells me she has the ability to be in the fourth grade. I'll bet she's one of the few actresses still working who can boast that they actually live on Hollywood Blvd."

A downtown crowd sat in on Evelyn's first real professional appearance. She's the youngest member of the Los Angeles Figure Skating Club and was the only none to show up at Pershing Square two Christmases ago when the group was to put on an exhibition at the portable skating rink. Like a veteran trouper, she glided over the ice for 90 minutes. She was 4 years old at the time.

"From this she won an audition on 20th Century-Fox's "Daddy Long Legs." Also on her credit sheet is "View from Pompey's Head," "The King and I," "Last Command," and the yet to be released "Wings of Eagles."

Most Affairs
In the television version of "Eloise" Evelyn plays a child living in New York's Plaza Hotel who doesn't actually take over control of the hostelry but manages to get into most of its affairs in one way or another.

I sat in on rehearsals after lunch. Evelyn was all over the place. Veteran actors and actresses including Ethel Barrymore, Hans Conreid, Louis Jourdan, Mildred Natwick, Slapsy Maxie Rosenbloom. Charles Ruggles, Monty Wooley and Kay herself seem to be awed by the youngsters boundless energy.

She's up against some mighty tough acting competition this coming Thursday. But you can safely wager the old homestead that nobody is going to come close to stealing the play except 7-year-old Evelyn Rudie. She's really "Eloise."