Too Cute!Neil Patrick Harris Reveals Daughter Harper Lost Her First Tooth — See the Pic!

Angelina Jolie and Brad Pitt

Knox Léon and Vivienne Marcheline Jolie-Pitt were born on July 12, 2008, in Nice, France and instantly became the most famous celebrity children in the world.

The now nine-year-old twins are Brad and Angelina's fifth and sixth children — the couple is also parents to sons Maddox Chivan, 16, and Pax Thien, 13, and daughters Zahara Marley, 12, and Shiloh Nouvel, 11.

The rights for the first images of Knox and Vivienne were jointly sold for a reported $14 million — knocking the photos of Jennifer Lopez and Marc Anthony's twins down the totem pole for the most expensive celebrity pictures ever taken. The proceeds were donated to the Jolie-Pitt Foundation.

Céline Dion and René Angélil

Céline had twin boys, Eddy and Nelson, on Oct. 23, 2010, after she and her late husband, René, experienced six former attempts at conceiving via in vitro fertilization.

The boys are named after Céline's favorite Algerian songwriter Eddy Marnay and former South African President Nelson Mandela.

The twins joined older brother René-Charles Angelil, who was born in January 2001.

Zoe Saldana and Marco Perego

Zoe and her hubby welcomed twin sons, Bowie and Cy, on Nov. 27, 2015. The couple are also parents to a younger son, Zen.

Mariah Carey and Nick Cannon

The singer and former America's Got Talent host welcomed twins Moroccan Scott Cannon (aka "Roc") and Monroe Cannon (aka "Roe") on the couple's third wedding anniversary, April 30, 2011.

Their son is reportedly named after the famous Moroccan Room in Mariah's lavish NYC apartment. His middle name, Scott, is Nick's middle name as well as his mother's maiden name. Monroe was named after Marilyn Monroe, who Mariah has publicly called her inspiration.

Neil Patrick Harris and David Burtka

On Aug. 14, 2010, the How I Met Your Mother actor announced he and his partner David were expecting twins via surrogate. Gideon Scott, a boy, and Harper Grace, a girl, were born in 2010.

Julia Roberts and Danny Moder

The Oscar-winning actress gave birth to twins Hazel Patricia and Phinnaeus "Finn" Walter* on Nov. 28, 2004.

Julia and her cameraman husband, Danny, later welcomed another son named Henry Daniel in June 2007.

Jennifer Lopez and Marc Anthony

After marrying longtime friend Marc in 2004, J.Lo gave birth to twins Maximilian David Muñiz and Emme Maribel Muñiz on Feb. 22, 2008.

The twins made their public debut in a March 2008 issue of People, for which the magazine paid a reported $6 million. The coveted photos of the twins became the most expensive celebrity picture ever taken at the time.

Julie Bowen and Scott Phillips

Both onscreen and off, Modern Family matriarch Julie is a mother-of-three! The actress gave birth to twin boys John and Gustav in 2009.

She and husband Scott, a real estate investor and software developer, also have an older son, Oliver, who was born in 2007.

Rebecca Romijn and Jerry O'Connell

The X-Men star gave birth to twin daughters Dolly Rebecca Rose and Charlie Tamara Tulip on Dec. 28, 2008.

The girls are named after singer Dolly Parton and Jerry's brother.

Sarah Jessica Parker and Matthew Broderick

SJP and Matthew welcomed twin girls, Marion Loretta Elwell and Tabitha Hodge, via surrogate on June 22, 2009.

The couple had been married for 12 years when their daughter-duo was born and have a son, James Wilkie, who was six years old when his sisters arrived.

Marcia Cross and Tom Mahoney

Best known for her role as Bree Van de Kamp on Desperate Housewives, Marcia and her stockbroker husband welcomed fraternal twin daughters, Eden and Savannah, on Feb. 20, 2007.