The Pretty Woman star, who has claimed the title three times before, is still winning over fans and making men swoon at age 42.
It is the twelfth time Roberts has made the top 100.
She joins 99 other celebrities on the list, including Diane Kruger, Channing Tatum, Zoe Saldana, Scarlett Johansson, Jake Gyllenhaal, Jennifer Aniston, Bradley Cooper, Katy Perry, Amanda Seyfried, Jennifer Lopez, Jessica Szohr and Robert Pattinson.
The show, set in a U.S. high school, has already attracted notable cameo appearances from Jennifer Lopez and Josh Groban, while Lady Gaga and Madonna have both given permission for their most famous tracks to be used in the routines.
And after working with Pretty Woman star Roberts on her new film, Glee creator Ryan Murphy is hoping she will join the cast of the hit TV programme.
He says, ""I just finished a movie with Julia, Eat, Pray, Love. She saw the rough cuts and fell in love with the show. I don't know if Julia's gonna do it, maybe. But she loves the show."
The actress has signed on to play a hooker with a heart of gold in a new U.S. cable film.
She tells TV Guide magazine, "It's (film) is sort of like Erin Brockovich in a brothel."
Brockovich is the tough but fair lawyer Julia Roberts played in Steven Soderbergh's 2000 movie.
Hewitt's boyfriend, Jamie Kennedy, couldn't be happier about the actress' new hard-hitting role, adding, "It's time for her to start showing everyone what I already know."
The Pretty Woman filmmaker landed a star-studded line-up for his latest release, including Julia Roberts, Jessica Alba, Jessica Biel, Jennifer Garner and Bradley Cooper.
Marshall admits onscreen chemistry between the actors was key to the casting, but he was sure Hathaway would hit it off with Grace immediately - because she's harboured feelings for the former TV star for years.
He says, "Julia Roberts... Bradley Cooper, she did a play (Three Days of Rain) on Broadway with him, 98 performances, they must have gotten along! We matched up.
"Anne Hathaway, she told me (about) this actor she once had a crush on - we hired him, Topher Grace; they kissed very well."
The director and star's fourth collaboration, which stars DiCaprio as a U.S. marshal investigating the disappearance of a patient at an insane asylum, is the best opening for the pair yet.
Their last Oscar-winning film, The Departed, debuted at $26.9 million (GBP16.8 million) in 2006. They previously worked together on Gangs of New York and The Aviator.
Meanwhile, star-studded romantic comedy Valentine's Day slipped to number two, with takings of $17.2 million (GBP10.8 million). The Garry Marshall film, which stars Julia Roberts, Jessica Alba, Jennifer Garner, Anne Hathaway, Ashton Kutcher and Bradley Cooper, now boasts a 10-day total of $87.4 million (GBP54.6 million).
James Cameron's Avatar remains strong at three with $16.1 million (GBP10.1 million) - two months after its debut. The
The sci-fi sensation's record-breaking U.S. total tallies in at $687.8 million (GBP429.9 million). Worldwide, the film has taken in $2.47 billion.
Rounding out the top five are Pierce Brosnan's Percy Jackson & the Olympians: The Lightning Thief and Benicio Del Toro's The Wolfman, with total earnings of $15.3 million (GBP9.6 million) and $9.8 million (GBP6.1 million) respectively.
The director landed a stellar cast, including Ashton Kutcher, Julia Roberts, Bradley Cooper, Anne Hathaway and Jennifer Garner, for the romantic comedy which topped the U.S. box office over the weekend (12-14Feb10).
He was wary of employing actors for crowd scenes who might have been overwhelmed by the starry cast - so he hit upon a novel solution.
Marshall says, "I've had a lot of relatives who were involved. Part of my thing is when you work with these stars, you have to make them comfortable. You surround them with people you can rely on.
"Bradley and Julia sat on that plane and seated next to them was my grandchild who won't say a word. She won't grab Julia and say, 'Give me an autograph.' She'll sit quietly. So we put family members, besides Diane, who is my assistant, and her husband sat behind them and didn't say a word. And with Ashton, my daughter was the other clerk with him, so he's comfortable."
Cupid struck on St. Valentine's Day weekend (12-14Feb10) as millions flocked to watch the romantic comedy, which stars Julia Roberts, Jessica Alba, Jennifer Garner, Anne Hathaway, Ashton Kutcher and Bradley Cooper, among others.
The box office figures are expected to swell by the end of Monday (15Feb10) as U.S. film fans take advantage of the Presidents Day holiday and three-day weekend.
Valentine's Day has already smashed the previous Presidents Day weekend record of $52 million (£32.5 million) set by Ghost Rider in 2007.
Meanwhile, Pierce Brosnan's Percy Jackson and the Olympians: The Lightning Thief enters at two with $31.1 million (£19.44 million), while Benicio Del Toro's The Wolfman grossed $30.6 million (£19.23 million) in its opening weekend to claim third place.
James Cameron's sci-fi blockbuster Avatar remains strong at four and last week's (05-07Feb10) number one movie, Dear John, rounds out the top five in fifth position.
The actress is part of a star-studded cast in the new Garry Marshall romantic comedy, which includes Julia Roberts, Jennifer Garner, Jessica Alba, Ashton Kutcher and Bradley Cooper.
And one particular day of filming left Biel buzzing around on set.
She says, "We shot both scenes on the same day. So in the morning I ate about 10 doughnuts; in the afternoon I ate about 18 or 20 chocolates. I was on a sugar high for days, it was crazy!"
The Roberts are among a host of Hollywood actors starring in the film, including Jennifer Garner, Jessica Alba, Jessica Biel and Bradley Cooper.
But instead of hanging out with the star-studded cast when she wasn't needed for filming, Emma found herself looking after her little cousins - five-year-old twins Hazel and Phinnaeus, and Henry, two.
Emma tells Us Weekly magazine, "I didn't have scenes with her, so I babysat the kids while she was on set. She really is just a mum, at the end of the day. She's totally normal, which I love."
She joins beauty icons Gabrielle Union, Hayden Panettiere, Vanessa Hudgens, Jennifer Garner, Diane Lane and Emma Roberts as the latest member of the Neutrogena family.
The School of Rock star says, "My friends and I have always loved the Neutrogena brand and their ability to help inspire confidence. So when I found out I was actually going to be part of the Neutrogena family I was really excited.
"I have always looked up to many of the actresses who are already Neutrogena Ambassadors, and others are my peers, so it is an amazing honour for me to be part of this incredible group."