Star Tracks: Celebs on Social

The tennis champ cuddles with daughter Alexis Olympia.

The Mayor actress jumps for joy during a sultry bedroom photoshoot.

Just one day after speaking out against producer Harvey Weinstein, the actress penned a sweet note to her daughter, Apple, on Instagram in honor of International Day of the Girl. "Everything I do in my life I do for this girl (and her brother)," the mom captioned the image.

The "Titanium" singer usually hides her face behind an elaborate wig, but she certainly was not hiding on Tuesday. She dared to bare not only her face but also her right breast.

The performers are total Disney darlings as they snap a selfie at Disneyland, where they spent the day with their kids.

"My curious, courageous one, I promise we'll work hard to make this place better for you and your sisters everywhere," mom Olivia Wilde captioned a photo of an intrigued-looking Daisy gazing out a window, in honor of her daughter's 1st birthday. "We've taken some hits recently, but I believe we are even more determined because of it."

The Top Chef host's daughter Krishna Thea is (literally) a mirror image of her famous mother. She captioned the snap with the hashtags: "#TwinningAndWinning #CantStopWontStop."

The mother of two shared a one-week update showing how she is healing on Instagram with a mirror selfie. "One week post op. Staples out. Steri strips on," Mollen, who welcomed son Lazlo with husband Jason Biggs, captioned the photo that showed white wound closure strips on her C-section scar.

The Golden Globe Award-winning actress decided to get the inside of her nostrils waxed and left nothing to the imagination when she shared the painful process she endured with her fans on Instagram. "Just say no," she wrote of the experience.

They're twinning! The pregnant sisters show off their uncanny resemblance during an impromptu photoshoot.

Well, that's one way to ring in her 21st birthday. The supermodel opts for a g-string on Tuesday.

Before Gunner Stone, there was just Speidi — enjoying some of their last moments as a duo by channeling The Lion King.

The 39-year-old father of two and infamous gossip blogger (whose given name is Mario Armando Lavandeira, Jr.) welcomed daughter Mayte Amor (via surrogate) on Oct. 4. "I am beaming with joy and pride as I share with you that my family has grown yet again," he wrote in the sweet picture’s caption, adding "she's perfect."

They're back on! Shortly after reconciling, the cute celeb couple treats themselves to beer in Dublin, Ireland.

The Modern Family actress supports breast cancer awareness month by sharing a short video documenting her latest mammogram. Standing in front of a mammography unit wearing a robe, she wrote "You have to do it!!!!"

Carter returns to social media on Saturday to show off the 30 lb. weight gain he experienced over "a few weeks" of focusing on himself and his health. “From 115 pounds to 145 in a few weeks,” Cater wrote on Instagram. “On the left 115. On the right 145 Continuing to focus on myself and my health. #proudofmyself #StressFree. Needed some time to heal and this is a direct result.”

Robin Thicke's girlfriend shows off her growing baby bump on Instagram in a sweet bikini selfie. "Already so in love with you," she captioned the picture.

We can thank Miss Tina Lawson for this adorable Queen Bey throwback, which proves the Grammy winner is the spitting image of daughter Blue Ivy.

The singer shows off her newly dyed gray hair on Instagram, clarifying that even though it looked like a purple-tinged silver in the photo, it was actually gray. "Btw (it’s grey)," she captioned the photo, which she put a heart-filled filter on.

The supermodel puts on a face mask to ring in her 21st birthday.

A short-shorts-clad Roberts is living the good life, enjoying a glass of champagne on a balcony.