In 1991, she moved to Los Angeles to study acting and her visa expired.
"I was an illegal immigrant in the United States," Hayek told the Spanish edition of V magazine, according to E Online. "It was for a small period of time but I still did it."
But unlike most Mexican immigrants Hayek was able to fix her immigration status, eventually get a green card and then become a U.S. citizen.
Her pathway to legalization was available because she came from a family with money in Mexico and she had the opportunity to study and was offered work as an actress in the United States.
But for the overwhelming majority of Mexicans there is NO pathway to legalization.
To become legal you need a family member who is a permanent resident or U.S. citizen to sponsor you. And for many even this process can take years - up to 15 or 20 - as there are long waiting periods.
For example, relatives who petitioned for family members from Mexico in 1992 and 1993 now are eligible for visas, according to the December 2010 Visa Bulletin from the U.S. State Department. It's only fast-track if you marry a U.S. citizen.
The only other option is if an employer sponsors you. Hayek also told V magazine that she faced discrimination as a young actress in Hollywood.
"I had to endure the worst time of all in terms of racial discrimination in Hollywood when I first started out," she told the magazine. "It was inconceivable to American directors and producers that a Mexican woman could have a lead role."
Yes that sounds awful Salma.
But it's worse for the dish washers, farm workers and factory workers who are undocumented immigrants - underpaid and exploited. These hard workers will have no chance at legalization unless Congress passes some type of immigration reform.
Unfortunately for them there is no Hollywood ending.