In the unpredictable world of Hollywood, a single film can redefine an actor's career, turning a forgotten figure or a performer stuck in a rut into a star. Sometimes, the key to this transformation lies in a surprising element: a shared title with previously unsuccessful ventures. Here are five such films that defied expectations, became blockbusters, and dramatically altered the destinies of actors involved.

1. Rocky (Sylvester Stallone)

Before Rocky (1976), Sylvester Stallone was a struggling actor. But the critical and commercial success of Rocky launched his action star career throughout the '70s and '80s. Stallone wrote himself into cinematic history with this underdog story, proving his talent both in front of and behind the camera. The film not only garnered critical acclaim and box office success but also earned Stallone an Oscar nomination and cemented his status as a leading man. Audiences still associate the actor with this role almost fifty years later.

2. Airplane! (Leslie Nielsen)

Leslie Nielsen was known for serious roles before Airplane! (1980). The Zucker brothers' anarchic comedy Airplane! didn't so much save Nielsen's career as completely reinvent it. Airplane! recognized his preternatural flair for deadpan, and a career as a comedy maven was born. He found a second act as an oblivious straight man, most notably Frank Drebin in the Police Squad TV series and Naked Gun films.

3. Pulp Fiction (John Travolta)

John Travolta's career had significantly declined before Quentin Tarantino cast him in Pulp Fiction (1994). The singing, dancing star of Grease had watched his career flatline throughout the Eighties. Travolta's turn as the shambling gangster Vincent Vega, reinvigorated his career, and saw him receive a surprise Oscar nomination. The film's unconventional format and gripping narrative brought it immediate acclaim transforming the lives of everyone involved including Travolta. It earned him a second Oscar nomination for best actor, and made him a highly sought-after leading man once again.

4. Gladiator (Russell Crowe)

Russell Crowe was a respected actor before Gladiator (2000), but the film catapulted him to global stardom. Crowe followed The Quick and the Dead up with one of the best modern noirs, L.A. Confidential. Ridley Scott's Gladiator made the actor a household name. Scott cast Crowe as Maximus, a Roman general who, after a massive betrayal, was enslaved and thrown into the Colosseum as a gladiator.

5. Iron Man (Robert Downey Jr.)

Robert Downey Jr. is one of the most famous actors to have pushed his acting career to the brink of extinction, only to claw his way back to the very top. Personal drama including a serious substance use disorder derailed his career by the 2000s. The 2005 noir comedy Kiss Kiss Bang Bang marked Downy's triumphant recovery. Iron Man (2008) was a massive gamble that paid off, revitalizing Downey Jr.'s career and launching the Marvel Cinematic Universe. His portrayal of Tony Stark resonated with audiences worldwide, making him one of the highest-paid and most beloved actors in Hollywood.