Radha Rani Amber Indigo Ananda Mitchell (born 12 November 1973) is an Australian actress. She began her career on television, playing Catherine O'Brien on the Australian soap opera Neighbours (1996–1997), before transitioning to working in Hollywood. Known for her work in the action and thriller genres, she is the recipient of an FCCA Award, as well as nominations for Fangoria Chainsaw, AFI, and Screen Actors Guild Awards.

Mitchell's credits include supporting and leading roles in films such as High Art (1998), Pitch Black (2000), Phone Booth (2002), Man on Fire, Finding Neverland, Melinda and Melinda (all 2004), Mozart and the Whale (2005), Silent Hill (2006), Rogue (2007), Surrogates, The Waiting City (both 2009), The Crazies (2010), Olympus Has Fallen (2013), London Has Fallen (2016), The Darkness (2016), The Shack (2017), Celeste (2018), and Blueback (2022). Outside film, she played the recurring role of Kelly on ABC Television's Troppo (2022).

She credits her name as being a result of her mother's experiences in India during the 1970s and her fascination with Indian philosophies. She grew up in Melbourne, just around the corner from the Como Centre—a multi-storey office, retail cinema and hotel complex, featuring the headquarters of Channel 10 Television—on Chapel Street, where her mother ran a shop. Mitchell attended St Michael's Grammar School in St Kilda. Her first credited screen role was that of an eleven-year-old girl from the Australian bush sent to live with her grandmother, on the ABC TV children's television series Sugar and Spice, which was broadcast between 1988 and 1989. Her experience in the series, along with the drama course she took at St Michael's, sparked her interest in acting. She then enrolled at Swinburne University of Technology, with the idea of becoming a psychologist. "I thought it was going to be group therapy, that we would go in there and talk about life and people and stuff like that. But it was all rats and stats. I didn't last beyond the first year." Instead, she obtained her Bachelor of Arts in literature and media studies.

Mitchell played the recurring role of Jodie Ryan in the sitcom All Together Now (1992–1993), and guest-starred in R.F.D.S. (aka The Flying Doctors), Phoenix (1993), Law of the Land (1993) and Blue Heelers (1994–96). After obtaining a ten-episode arc as a parachute instructor in Neighbours in 1994, Mitchell returned to play the regular role of Catherine O'Brien, a strong-minded and opinionated student, from 1996 to 1997. The series brought the actress to a wider exposure from audiences.

Mitchell quickly "established herself as a versatile and accomplished fixture on the moody art-house flick circuit". As noted by The Guardian, she launched "her assault on the indie scene by 'cornering the market on the lesbian ingenue'". Her film debut came in the role of a gay University of Melbourne film student in the romantic comedy Love and Other Catastrophes (1996), which grossed US$1.6 million at the Australian box office. It was her next project, Lisa Cholodenko's Independent Spirit Award-winning independent drama High Art (1998), alongside Ally Sheedy, that gave Mitchell her first impression on American audiences. She was acclaimed for her performance of a young female intern at a magazine company who becomes involved with a drug-addicted lesbian photographer. Roger Ebert wrote that "High Art is so perceptive and mature it makes similar films seem flippant. The performances are on just the right note, scene after scene, for what needs to be done ...". IndieWire listed it as #7 of "The 15 Greatest Lesbian Movies of All Time", while Autostraddle listed it as #31 of "100 Best Lesbian Movies Of All Time" in 2015. She played one half of a house sitting couple in the psychological drama Cleopatra's Second Husband (also 1998).

In 1999, Mitchell starred as the former girlfriend of a lesbian make-up artist in the short drama Sleeping Beauties and as the pampered, bratty girlfriend of a champion rugby player in the drama Kick. While Sleeping Beauties premiered at the 1998 Sundance Film Festival and went on to play at over thirty film festivals, Kick had a brief cinema screening in Europe before it was released on DVD.

Mitchell was cast as Carolyn Fry, a docking pilot, in the science fiction horror film Pitch Black (2000), opposite Vin Diesel. She found the experience of acting in a studio film "physically challenging", but was eager to take on the role, explaining: "Well, it's an interesting script, great character, shot in Australia, get to go home, you know, a whole range of reasons. And because I guess it's not something I would often have the opportunity to do; it's a genre piece and I felt it was an opportunity to learn". Despite mixed reviews from critics, the film was a sleeper hit, grossing over US$53 million worldwide and developing its own cult following. In 2000, she also starred as an expecting mother in the psychological drama Everything Put Together, which was nominated for the Grand Jury Prize at the Sundance Film Festival, and as the love interest of a lawyer in the romantic comedy Cowboys and Angels [fr] .

In 2001, Mitchell played a woman giving monologues to camera in the drama Ten Tiny Love Stories, a diner waitress in the comedy Nobody's Baby and the owner of a remote roadside diner in the thriller When Strangers Appear. Her next film release was the crime drama Dead Heat (2002), in which she played the wife of a police officer. Joel Schumacher's thriller Phone Booth (2003), opposite Colin Farrell, featured her as the wife of a young arrogant publicist who becomes a victim of a mysterious caller who threatens to harm him. It was a critical and commercial success, grossing US$97.8 million worldwide. She starred as the first woman to sail around the world solo in the horror film Visitors (also 2003).