It is widely acknowledged that workplace romances are a definite no-no; clearly, some famous actors and actresses didn't get the memo. From classic romantic duos Bogey/Bacall and Spencer/Tracy to contemporary pairings like "Bennifer" and "Brangelina", since the inception of cinema, thespians have taken on-set relationships from reel-life to real-life.

Julia Roberts and Kiefer Sutherland's hearts skipped a beat while filming Flatliners (1990). Tom Cruise admired a young Aussie actress named Nicole Kidman and had her cast opposite him in Days of Thunder. The movie Seven ended with Gwyneth's head in a box - and on the pillow of costar Brad Pitt. Johnny Depp tattooed "Winona Forever" on his arm after meeting Ms. Ryder while shooting Edward Scissorhands; Warren Beatty romanced countless costars before one last fling on the 1990 set of Dick Tracy with a breathless Madonna; Matt Damon and Minnie Driver held hands between takes of Good Will Hunting (1997); Ryan Gosling and Rachel McAdams thrilled rabid fans of The Notebook by actually falling for one another; Heath Ledger and Michelle Williams connected making Brokeback Mountain and garnered two Oscar nods and daughter Matilda. The list goes on: Jude Law and Sienna Miller (Alfie); Jennifer Aniston and Vince Vaughn (The Breakup); Kate Hudson and Owen Wilson (You, Me and Dupree).

Jennifer Aniston and Vince Vaughn - 'The Breakup' - 2006)

Statistically, average workplace romances have around an 80% failure rate and Hollywood is no exception. Julia Roberts skipped out on her wedding to Kiefer and ran off with his buddy Jason Patric. Kidman claimed she had Eyes Wide Shut when Cruise left her just shy of their 10th anniversary (Tom later went on to have a relationship with another costar, Penelope Cruz, before marrying current wife Katie Holmes.) Pitt and Gwynnie fizzled and Johnny Depp had his tattoo altered to read "Wino Forever". Beatty and Madonna went kaput and he finally settled down with Annette Bening, whom he met shooting Bugsy (1991). Minnie Driver reportedly found out about her breakup with Damon while watching him on "Oprah". Aniston and Vaughn was a blip, Gosling and McAdams split in 2007, Kate and Owen separated several before she moved on to Lance Armstrong and Jude Law cheated on Sienna Miller - with the nanny.

So consenting singles meet and mingle under the klieg lights from time to time - it's to be expected. But what happens when a star has a significant other, or even - gasp - a spouse back at home, awaiting the wrap of production? In the early 70's, Love Story's Ali MacGraw braved the clout of husband and studio head Robert Evans to run off with costar Steve McQueen (The Getaway). Laura Dern (Jurassic Park) was stunned in 1991 when her longtime boyfriend Billy Bob Thornton eloped with his Pushing Tin costar Angelina Jolie (Later, many would blame Jolie for the breakup of a much more famous pairing, Jennifer Aniston and Brad Pitt). America's sweetheart Meg Ryan threw her reputation to the wind when she cheated on hubby Dennis Quaid with bad boy Russell Crowe while filming 2000's Proof of Life.

Meg Ryan and Russell Crowe in 'Proof of Life' - 2000

Ryan Phillippe's "friendship" with Stop-Loss costar Abbie Cornish allegedly played a part in the dissolution of his marriage to Reese Witherspoon. Both actress Anne Heche and director Robert Rodriguez went through ugly divorces after their relationships with James Tupper ("Men in Trees") and Rose McGowan (Planet Terror) respectively. Classic Hollywood was not immune to scandal: A very married Ingrid Bergman became pregnant by her Stromboli director Roberto Rossellini in 1950, prompting condemnation by Congress, while heavy-drinking Welshman Richard Burton slipped off his wedding ring on the 1963 set of Cleopatra to hit the sheets with Elizabeth Taylor, already on her fourth marriage (Burton and Taylor went on to marry and divorce - twice).

Reese Witherspoon and Ryan Phillippe - 2005

Clark Gable conveniently forgot about his wife when he laid eyes on ingénue Loretta Young (The Call of the Wild, 1935), a dalliance that produced a secret daughter, Judy. Behind the romantic mystique of two storied romances: Bogie traded in his wife for 19 year-old Lauren Bacall and devout Catholic Spencer Tracy refused to divorce his wife, choosing companionship with Katharine Hepburn for a quarter of a century (whom he costarred with a whopping 25 times!). However, the fate of these illicit affairs seem to lend credence to Karma - with the exception of Hepburn/Tracy, not one of them lasted (Cornish and Phillippe outcome pending).

If a romance on a film set sours, the inevitable wrap (feature shoot times average 6 months) serves as some consolation. Television actors who get involved on the set of a series, however, often have to continue working with former paramours indefinitely. Heartthrob Chad Michael Murray crushed a million tween hopes when he married his "One Tree Hill" costar Sophia Bush. The sadness of adoring fans was short-lived, like the marriage: The young costars split months later, yet still work together to this day. Other stars who put their professionalism to the test: Marilu Henner slept with both Judd Hirsch and Tony Danza, her costars in the 70's series "Taxi"; Matthew LeBlanc took up with "Joey" costar Andrea Anders despite a recent marriage and infant daughter; Jennifer Garner separated from actor Scott Foley (whom she met on the set of "Felicity") then fell for "Alias" costar Michael Vartan only to split with him before the show's conclusion. Ironically, Jen is now happily married to yet another costar - Ben Affleck (Daredevil) with whom she's currently expecting her second baby.

Ben Affleck and Jennifer Garner - 'Daredevil' 2003

Aside from the interest of a celebrity-obsessed media and interested public, the personal relationships of actors are nobody's business, right? Right - unless you're the studio backing a picture potentially affected by a possible scandal. Production heads were ringing their hands when Burton and Taylor aroused negative publicity and the ire of the Vatican for their open affair during Cleopatra's Roman shoot. Bennifer, aka Ben Affleck and Jennifer Lopez, fell in love on the set of Gigli (2003) and consequently tanked both that film and Jersey Girl (2004). A public disgusted with Meg Ryan's behavior rendered Proof of Life box office poison, while the combustible coupling of Kim Basinger and Alec Baldwin overshadowed the 1991 film The Marrying Man and landed the director in the hospital for stress-related exhaustion.

Production liaisons aren't always doomed: Defying the odds are longtime couples like Paul Newman and Joanne Woodward (married since 1958) whose palpable chemistry is evident in The Long Hot Summer; the late actor Ossie Davis and his bride Ruby Dee who met performing in "Jeb" on Broadway in 1946 and were married until his death in 2005; Kyra Sedgwick ("The Closer") who is only separated by one degree from Kevin Bacon, her husband of twenty years (met on the TV Movie set of "Lemon Sky" in 1988) and two famous couples still living together in unwedded bliss - Tim Robbins and Susan Sarandon (met on Bull Durham, 1988) and Kurt Russell and Goldie Hawn (met on Swing Shift, 1984). Who knows: Someday we may be able to add Gosling and McAdams to the list, as they've been recently spotted spending time together once again.

Kyra Sedgwick & Kevin Bacon together since 1988 - Kurt Russell and Goldie Hawn met on Swing Shif in 1984

So will America's most famous co-stars in love Angelina Jolie and Brad Pitt continue their path of harmonious domesticity, or will it all end in a shootout ala the flick that united them, Mr. And Mrs. Smith? Time will tell... The fact is that the success or failure rate of on-set romances is of little consequence to those who embark on the relationships. As the late, great auteur Alfred Hitchcock wryly observed, "All love scenes started on the set are continued in the dressing room after the day's shooting."

Story by Shannon Peace

Starpulse contributing writer