galleryLook Who's Irish!03.15.10galleryLook Who's Irish!Will Christina Aguilera, Emilio Estevez, and Barack O'Bama be celebrating St. Patrick's Day this year? See 16 stars with surprising Irish ancestry.03.15.10 4:33 PM ETJennifer Graylock / AP Photo Robert De Niro He may have earned his first Oscar as the young Vito Corleone in The Godfather: Part II, but Robert De Niro’s real father is of both Italian and Irish descent. His father, Robert De Niro Sr., was the son of Dennis O’Reilly and Mary Burns, and the famous Robert De Niro Jr. spent some time visiting the land of his forefathers as a teenager in 1962. “I hitchhiked from Dublin to Galway and took the ferry to the Aran Islands, then I went down through the south,” he told The Independent. “People gave me blankets for sleeping outside and I had breakfast with them in the morning. They were very friendly." Timely enough, up next for the current Limitless star is Martin Scorsese’s highly anticipated project The Irishman. Joel Ryan / AP PhotoLindsay LohanShe’s since gone black, blonde, and brown, but troubled actress Lindsay Lohan once looked like quite the Irish stereotype with the natural red hair and freckles that made her famous in Disney’s Parent Trap reboot in 1998. She is reportedly 75 percent Irish and before her infamous momager wed her father, Dina Lohan was known as Donata Sullivan. Though Lindsay’s constant run-ins with the law would indicate she hasn’t exactly been the most fortunate celebrity, she still happily acknowledged her roots on St. Patrick’s Day last year, tweeting, “ Luck Of The Irish!”Jorge HerreraEmilio EstevezThe former Brat Pack member and the older brother of Charlie Sheen (born Carlos Estevez) was the all-American boy in the 1980s. And unlike his now infamous brother, the son of actor Martin Sheen (born Ramón Estevez) did not adopt his father’s stage name. Estevez’s paternal grandfather was of Spanish descent, but his paternal grandmother, Mary Ann Phelan, hailed from Ireland. When it came to directing and writing the 2006 Robert F. Kennedy biopic Bobby, Estevez said in an interview that Weinstein Company head Harvey Weinstein would joke about his ancestry. “We have a fight now and again,” he admitted. “It’s all good-natured, but he accuses me of being an Irish thug.”J. Scott Applewhite / AP Photo,J. Scott ApplewhiteBarack ObamaEveryone knows about Barack Obama’s Kenyan roots and his mother’s Kansas upbringing. However, the president has yet to embrace his great-great-great-grandfather Falmouth Kearney, an Irish immigrant who crossed the pond in 1850. "He’s as much Irish as he is Kenyan," Irish American Democrats president Stella O’Leary told Politico. "He’s been very wrapped up in his African-American heritage. But we will welcome him with open arms." Anything to get an O’Bama in the White House.Chris Pizzello / AP Photo,Chris PizzelloChristina AguileraSure, Christina Aguilera can move to Latin rhythms, but she could also break out a little Riverdance—the pop princess was born to an Ecuadoran father and an Irish mother. In 2006, Aguilera even returned to her roots for her first wedding anniversary with husband Jordan Bratman—the pair spent six days in Ireland.Junko Kimura / Getty ImagesHarrison FordAdam Sandler may have been proud to claim Harrison Ford as "a quarter-Jewish" in " The Chanukah Song" but in fact the actor is half-Jewish—and half-Irish. Ford gets his Irish blood from his father, Christopher, and, when asked on Inside the Actor’s Studio which side he identified with more, Ford said he is "Irish as a person, but I feel Jewish as an actor."Dan Steinberg / AP Photo,Dan SteinbergAlicia KeysAlicia Keys uses her complex ethnic background to her advantage. In addition to being black, Italian, and a little Scottish, the sultry singer is also a wee bit Irish. "Being of mixed background influences everything in my life and music," she has said.Charles Sykes / AP Photo,Charles SykesBen StillerBen Stiller was once asked by Time magazine how it feels to be identified as a "big Jew" (his father is comedian Jerry Stiller) considering he is also half-Irish (mom is comedian Anne Meara). Stiller noted that he’s "very proud" of the Irish ancestry, but that the homeland would be the last place on his mind if he ever needs to cope with heartbreak again. "I went there when I broke up with my girlfriend to get over [it]. And it was the wrong place to go," Stiller admitted. "All you do is drink Guinness and cry and look at the ocean and want to kill yourself." Retna,© RD / Roe / Retna DigitalAna OrtizDespite her prominence as a Hispanic actress, Ugly Betty’s Ana Ortiz is also part Irish "Nobody ever casts me as anything other than Latin," said Ortiz, whose father is Puerto Rican and whose mother is Irish-American.Jason Merritt / Getty ImagesJohn TravoltaJohn Travolta may be best known for playing Vinnie Barbarino and Tony Manero, but he grew up in an Irish home. His mother was Irish, and his father was a second-generation Italian who was more interested in trading in his Old World traditions for more modern, American ones. So, by default, the Irish culture became dominant in the Travolta household of eight.Walter McBride / Retna,© Walter McBride / Retna Ltd.John StamosJohn Stamos, most famous for his role on Full House as Uncle Jesse Katsopolis, got his Greek blood from his father and his Irish blood from his mother. Originally, Stamos’s character on Full House , Jesse Katsopolis, was named Adam Cochran.Carlos Diaz / Retna,(c) Carlos Diaz / Retna LtdGwen StefaniGrammy-winning singer Gwen Stefani also comes from a multiethnic background: She was born in Southern California to an Italian father and a mother, Patti Flynn, of Irish and Scottish descent.AP Photo,AnonymousMarlon BrandoMarlon Brando died in 2004 before he could finish Divine Rapture set in the town of Ballycotton in Cork. The movie, which was to feature Brando, Johnny Depp, and Debra Winger, was set around an elderly Irish priest who believed in miracles. Brando may have gotten his fascination with Irish tales from his mother, Dorothy Pennebaker, who was of Irish descent.Graham Jepson / Retna ,Graham Jepson / TSPL / Camera Press / Retna Ltd.Janeane GarofaloComedian Janeane Garofalo is half-Irish and half-Italian, but in the 1997 movie The Matchmaker, she got in touch with her Gaelic side. Garofalo played Marcy, assistant to Sen. John McGlory, who is desperate for Irish votes during his reelection. As a solution, the senator sends Marcy to trace his relatives in Ireland, where she ends up at the annual Matchmaking Festival.PBS,Photo: Jeffrey DunnHenry Louis Gates Jr.During a PBS series on African-American ancestry, Harvard professor Henry Louis Gates Jr. learned he was a descendant of an Irish immigrant and a slave girl. Gates has ancestors associated with the Niall of the Nine Hostages, a fearless Irish leader from the fourth and fifth centuries. Oddly enough, Sgt. James Crowley, who infamously arrested Gates at his home in 2009, can also trace his ancestry to Niall of the Nine Hostages.Gaas / AP Photo,GaasKathy Ireland Despite her last name and recent appearance with a St. Patrick’s Day-ready Mickey Mouse, supermodel and design entrepreneur Kathy Ireland was born in Glendale, Calif., to American parents. Though presumably, somewhere along the way, a relative must have had a touch o’ Emerald Isle blood.