Alba again surprised the world in 2007 when she announced she was pregnant and engaged to the baby's father, producer Cash Warren. Now, with 19-month-old daughter Honor Marie, just finding time alone with her husband is a challenge.
Her real-life Valentine's Day, she told a reporter: "it's just a nice excuse to go on a date with my husband."
The "Pretty Woman" star may be a happily married mom of three now, to husband-cinematographer Danny Moder, but it wasn't always so.
Before Moder, Roberts bounced from boyfriend to boyfriend, breaking an engagement and ending a marriage along the way. At 19, Roberts moved in with then 35-year-old Liam Neeson, whom she dumped for her "Steel Magnolias" co-star Dylan McDermott.
After "Flatliners," she and co-star Kiefer Sutherland got engaged but Roberts reportedly called off the wedding days before the ceremony, then ended up in the arms of Jason Patric. Then, she surprised the world with her secret elopement to singer Lyle Lovett, but the marriage ended less than two years later.
After Lovett, Roberts dated actor Benjamin Bratt for three years, telling McCalls he was "all a girl could ever ask for." But Bratt reportedly split with Roberts because of her infidelity.
Photographed strolling in Paris with husband Moder after the Golden Globe awards, Roberts, at 42, finally looks happy in love. Presumably, she's pretty happy in her career as well -- according to New York Magazine's Vulture blog, she got paid $500,000 per minute to appear in "Valentines Day."
The 27-year-old actress, whose three-year romance with Justin Timberlake is often said to be on the rocks, reportedly has no plans to celebrate Valentine's Day with the singer because she is too busy with work.
She told a reporter, though: "I love Valentine's Day. It's great to take a day out and celebrate loving and caring for people ... It's great."
But what people really want to know is whether the couple is still together. Last fall, break-up rumors exploded last fall with even Timberlake's grandmother fanning the flames with her comment to a British magazine: "Jessica was keen to marry but Justin isn't ready."
E! gossip columnist Ted Casablanca said the couple lacks spark.
"It's not working," Casablanca told ABCNews.com. "It's almost like they cancel each other out; same age, same look. There's no heat."
Biel, who dated Derek Jeter and Ryan Reynolds before Timberlake, called the split rumors "weird and sort of bizarre to deal with" in an interview with the UK's Independent in November.
Meanwhile, she has admitted to having a girl crush on two of her "Valentine's Day" co-stars, Roberts and Jennifer Garner.
"It's like, you're beautiful, you're cool, you look and seem like somebody I would want to hang out with and your career is awesome," Biel told a reporter about Garner.
At 37, Garner has been bouncing around Hollywood for some time but has still managed to avoid many of the pitfalls of romance.
After ending her three-year marriage to Scott Foley, whom she met on the set of "Felicity," Garner dated her "Alias" co-star Michael Vartan for about a year, before linking up with Ben Affleck.
Affleck proposed to Garner on her 33rd birthday while she was pregnant with their child. Married nearly five years and with two young daughters, Garner said her definition of romance has changed.