Just over four years ago they were up and coming soloists in the Soviet Union - yet they were performing only about once a month with the 280-member Bolshoi Ballet Company in Moscow.
Now, having danced almost every night this past summer with the New York City Ballet (visiting London, Copenhagen, and Paris), they are in the midst of a US tour with their own mini-company of 10. Their dramatic change of life style, their successful jump from East to West, reads like a Hollywood script: ''Sugar Plum Fairy'' ballerina Valentina meets her dark, handsome Prince Leonid, marries him, and they escape together to freedom.
Unlike many of their defector colleagues from the Soviet Union, who joined large companies and stayed with them, Valentina and Leonid Kozlov have worked with a number of small companies in different countries, gradually expanding their limited Bolshoi repertoire.
Now it is all paying off. ''She dances like cream on ice,'' says noted New York critic Clive Barnes. Anna Kisselgoff has written in the New York Times that Leonid is ''polished. . . . With classical lines and clean finishes.''
Leonid had already graduated from the Moscow choreography school - training ground for Bolshoi dancers - when blond Valentina was accepted to the school at the age of 9.
It was not until 1973 that their paths crossed, and then it was in the West, in New York City. They were on separate tours of the US, he with the Bolshoi and she with the school.
They met again at a reception in the White House. Two months later, back in Moscow, they were married and both dancing with the Bolshoi.
In such a large company with a definite pecking order, the opportunity to break through and to be a top star was rare.
In 1979, the company set off on a tour to three US cities, New York, Chicago, and Los Angeles.
''We had decided before we left Moscow to leave the company,'' Leonid told me the other day in an interview in London. ''We would go for walks to discuss our plans (because of the fear of electronic surveillance in their apartment) but we were certain it was right to go.''
Imagine their dismay when at the start of the tour, top soloist Alexander Godunov made his own dramatic leap to freedom, becoming the first Bolshoi dancer to defect (the others had been from the Kirov). Headlines grew even larger when Godunov's dancer wife, Lyudmilla Vlasova,cq was held at Kennedy Airport on a grounded Aeroflot jet for three days while US authorities decided whether she was returning to Moscow voluntarily. They eventually let her go.
''Were you afraid that your plan would be discovered, or that greater supervision would make it impossible?'' I asked them.
''No, we were only afraid that the whole company would be sent back to Moscow early, and there'd be no more chances,'' Leonid replied.
Leonid was handed Godunov's part of Tybalt in ''Romeo and Juliet'' and there were ''hints'' that when he returned home, many more roles would be made available to him.
''There was no one else on the tour who knew the Tybalt role,'' Leonid said. ''So Valentina and I decided that I must dance every Romeo and Juliet ballet - if not, what would the company have done?''
On Sept. 16, 1979, Leonid danced Tybalt (''it was the best ever I did'') and Valentina the role of one of Juliet's friends, for the last time for the Bolshoi. It was at the Shriners' Auditorium in Los Angeles.
They then quietly changed and slipped out of a side door into a waiting car in which they stayed all night.
Their defection was not political. Nor was it the result of bitterness with Bolshoi officials. In our interview Leonid spoke warmly with praise and gratitude for the controversial artistic director of the Bolshoi, Yuri Grigorovichcq.
''But here we have so many opportunities to dance - every day if we want - and what we want,'' Valentina said.
Variety has been the key word in the past four years.
They have appeared with numerous different companies such the Caracas Company and the London Festival Ballet. A two-year stay with the Australian Ballet Company saw new dramatic roles for her, and a chance to choreograph for him.
Last winter produced yet another variation when both starred on tour in the musical revival of ''On Your Toes.'' It meant speaking clearly in English (which both have mastered) and dancing in a most non-Bolshoi way: jazz, tap, etc. The critics were warm.
This August, both danced in Balanchine's ''Symphony in C'' with the New York City Ballet (NYCB) in London. They had sharpness and clarity of line. Valentina brought Russian tradition and technique, while Leonid showed Soviet male bravado and virility.
Both have managed to adapt their lyrical Bolshoi style to fit in with Balanchine's more active, tighter movements.
Their company while on leave of absence from the NYCB includes seven Americans (one of them Varna International Competition gold medalist Katherine Healey), two Australians, and a Romanian.
''There is nothing to compare with Soviet training,'' Leonid said. ''It is so thorough and technically perfect and just right for the classics. But you don't need those same technicalities as much with the newer dance in the West. Here you concentrate on the whole feeling and not just on correct placement.''
The Kozlovs and their company will be appearing in Ann Arbor, Mich., Oct. 26; San Jose, Calif., Oct. 31; New Orleans, Nov. 1 and 2; Houston, Nov. 3 and 4; Denver, Nov. 5; Memphis, Tenn. Nov. 8; Buffalo, N.Y., Nov. 11 and 12; Chapel Hill, N.C., Nov. 14; Tulsa, Okla., Nov. 15; Oklahoma City, Okla., Nov. 16.