It had to happen someday. Spain would finally produce a lavish film version of its greatest novel, ''Don Quixote.'' What is less predictable is that the quintessentially Spanish work should be filmed in collaboration with the Soviets.
This first agreement for a major Spanish-Soviet television production comes after 40 years of an anti-Soviet regime that blamed Moscow for the ills of the republic and the civil war. For a generation of Spaniards who were brought up with the idea, among others, that Soviets had horns on their heads, Don Quixote, Spain's national myth, is now to be incarnated by a Soviet actor in a Spanish production.
Although the agreement was only signed in February, the project was proposed by the Soviets several years ago and stems from a longstanding veneration for the figure of Don Quixote in the Soviet Union. Everyone from Pushkin to Lenin has apparently read Cervantes's work, and traveling Spanish producers were amazed to find copies of the novel and figurines of Don Quixote in the shops of the remotest Russian towns.
The project far outdoes any previous Spanish TV production in cost and ambition: about $6.5 million for nine installments of an hour and a half, each with Spain as the main contributor. French cinema will bear a minor share of the cost. To be completed by 1986, filming should start this fall on location in Soviet Georgia, southern France, and of course Spain's Mancha region with its windmills.
As a universal work where any possible interpretation may be given to the story of the tall, thin hidalgo (nobleman) who goes out on his faithful horse with his mad dreams and lofty ideals to do good in the world, it may be asked how the Soviets view the quest of Don Quixote. A successful movie version of Don Quixote was already produced by the Soviets in the '50s which made various social statements on the evils of the times.
When pressed about possible conflicts, the Spanish producer Jorge Sanchez said it was ''delicate.'' He conceded that they were still negotiating over the artistic line to follow. As great admirers of the Spanish artist Dali, the Soviets seemed to have a marked penchant for surrealist details which appear to make the Spaniards uncomfortable. They want to remain as realistic as possible and faithful to the 17th-century interiors.
With previous super-productions, such as ''Santa Teresa de Avila,'' currently showing, Spanish television has taken great care in the handling of national myths, stressing visual and historical details over exploring deeper interests, perhaps as a way of playing it safe with television viewers. In the case of the Don Quixote coproduction, the Spanish team may be understandably cautious. After all, the series will be directed by the Soviet director Revaz Chkeidze and the character of Don Quixote played by a Soviet actor, leaving the role of Sancho Panza, Quixote's down-to-earth servant, to a Spanish actor.
''Of course it hurt to let Don Quixote out of our hands,'' says Jorge Sanchez. The Spanish producer defends the choice, however, saying that Sancho, with his simple earthiness and peasant ruse, is closer to the Spanish character than the untouchable ''showcase figure'' of Don Quixote. Besides, as the film unfolds true to the novel, Don Quixote will show his human failings and Sancho Panza will be touched by his master's noble ideals.
As for the joint Spanish-Soviet production, a spokesman for the Soviet Embassy here in Madrid qualified the project as ''an important cultural event for Spanish and Soviet television, given the importance in both cultures of the Don Quixote figure . . . his great humanism . . . a fighter for the good of all.'' And no further questions, please.