Woody Allen and Mia Farrow : In the 1980s and early ‘90s, Farrow’s relationship with director Woody Allen resulted in numerous film collaborations. She appeared in nearly all of Allen’s critically acclaimed films during this period, including leading roles in Broadway Danny Rose, The Purple Rose of Cairo, Hannah and Her Sisters (playing the principal title role), Radio Days and Alice (1990), again as the title character. Farrow also played Alura, mother of Kara (Helen Slater), in Supergirl (1984) and voiced the title role in the animated film The Last Unicorn (1982). She also narrated several of the animated Stories to Remember. This info is from Wikipedia.
Julie Andrews and Christopher Plummer were in the movie The Sound of Music and the made for TV stage play adaptation of On Golden Pond
Robert Redford and Paul Newman were in The Great Gatsby and Butch Cassidy and the Sundance Kid.
Shirley Temple and Bill (Bojangles) Robinson danced together in The Little Colonel, The Littlest Rebel, Rebecca of Sunnybrook Farm and Just Around the Corner.
Juliet Stevenson and Alan Rickman were in The Search for John Gissing and Truly, Madly, Deeply
Alan Rickman and Emma Thompson were in Sense and Sensibility and Love Actually
Alan Rickman and Hugh Grant were in Sense and Sensibility and Love Actually and An Awfully Big Adventure
Emma Thompson and Anthony Hopkins were in Remains of the Day and Howard’s End
Humphrey Bogart and Lauren Bacall were in To Have and Have Not, Key Largo, The Big Sleep and Dark Passage.
Jack Lemmon and Walter Mathau were in The Odd Couple, Grumpy Old Men and The Sunshine Boys