“Bittersweet Love” is a 1976 American DeLuxe Color romantic drama film directed by David Miller (his final film), written by Adrian Morrall and D.A. Kellogg, starring Lana Turner, Robert Lansing, Celeste Holm, Robert Alda, Scott Hylands and Meredith Baxter-Birney in Panavision.
Michael and Patricia meet in an unusual way – while he is on a date and is trying to retrieve his date’s car keys from a fountain. When Michael’s date abandons him, he hangs out with Patricia and these two nice young people soon find themselves falling in love. They decide to wed and hold the ceremony in Canada, where Michael’s family lives. Patricia’s parents, who have been on a lengthy cruise and have never met Michael, cannot attend, but they meet their new daughter-in-law soon afterward. While reviewing pictures from the wedding, Michael’s mother is shocked to discover that she knows Patricia’s father. Even more shocking is the revelation that Patricia’s father is also Michael’s father, the result of a one-night stand many years before, and that the happily married couple are therefore half-siblings. To make matters worse, it turns out that Patricia is pregnant. The rest of Bittersweet Love is taken up with Michael and Patricia deciding what they should do about this situation, as well as with reactions and advice from their family members.

Lana Turner plays Claire, Michael’s mother.

Lana had been in the dream factory since she was 15 years old and never seriously cultivated any interests that exercised her creativity as much as films did. But her last good film was “Madame X.” Besides her last films were poorly distibuted.

From the American Film Institute: “Bittersweet Love” received mixed reviews, several of which placed it in the “woman’s picture” genre. While the 29 Oct. 1976 HR called it “a lush, romantic film,” the 27 Oct. 1976 Var described the romantic aspects as “exceedingly tedious and clichéd,” and the 28 Oct. 1976 LAT considered the plot highly implausible.

Clip:

You can watch the film here.

Lana Turner did a lot of movies. She really loved being a moviestar.
Here are the most important films in which she starred. Just click the links for more info, photos and videos.

20 April 1937: A Star Is Born
9 Oct. 1937: They Won’t Forget
24 Oct. 1937: The Great Garrick
1 Jan. 1938: The Adventures of Marco Polo
22 July 1938: Love Finds Andy Hardy
12 Aug. 1938: Rich Man, Poor Girl
9 Dec. 1938: Dramatic School
28 April 1939: Calling Dr. Kildare
18 Aug. 1939: These Glamour Girls
29 Sept. 1939: Dancing Co-Ed
19 April 1940: Two Girls on Broadway
19 July 1940: We Who Are Young
25 April 1941: Ziegfeld Girl
12 Aug. 1941: Dr. Jekyll and Mr. Hyde
2 Oct. 1941: Honky Tonk
18 Febr. 1942: Johnny Eager
27 Aug. 1942: Somewhere I’ll Find You
1 April 1943: Slightly Dangerous
19 Aug. 1943: Du Barry Was A Lady
13 Nov. 1943: The Youngest Profession
23 Aug. 1944: Marriage Is a Private Affair
8 March 1945: Keep Your Powder Dry
1 Oct. 1945: Week-End At The Waldorf
2 May 1946: The Postman Always Rings Twice
5 Nov. 1947 : Green Dolphin Street
1 Nov. 1947: Cass Timberlane
29 April 1948: Homecoming
20 Oct. 1948: The Three Musketeers
1 Sept. 1950: A Life Of Her Own
2 March 1951: Mr. Imperium
5 Sept. 1952: The Merry Widow
25 Dec. 1952: The Bad And The Beautiful
25 Aug. 1953: Latin Lovers
1 May 1954: Flame And The Flesh
7 Sept. 1954: Betrayed
13 May 1955: The Prodigal
4 June 1955: Sea Chase
14 Dec. 1955: The Rains Of Ranchipur
12 Jan. 1956: Diane
13 Dec. 1957: Peyton Place
30 Jan. 1958: The Lady Takes A Flyer
2 May 1958: Another Time, Another Place
30 April 1959: Imitation Of Life
23 June 1960: Portrait In Black
19 July 1961: By Love Possessed
2 Nov. 1961: Bachelor In Paradise
25 Dec. 1962: Who’s Got The Action?
24 Febr. 1965: Love Has Many Faces
27 April 1966: Madame X
30 April 1969: The Big Cube
7 Nov. 1974: Persecution
27 Oct. 1976: Bittersweet Love
31 Oct. 1980: Witches Brew
21 May 1982: Dead Men Don’t Wear Plaid

Sources: Wikipedia, IMDB, Rotten Tomatoes, Lana’s biography “Lana, the Lady, The Legend, The Truth“, “The Films Of Lana Turner” by Lou Valentino and “Lana Turner, The Memories, The Myths and The Movies” by Cheryl Crane.