Kate Hudson shares rare photo of her growing sons

Kate Hudson's sons are getting so big!

The "Almost Famous" actress took to Instagram late on Sunday night to wish her youngest son, Bingham Hawn Bellamy, a happy birthday with an adorable photo of him posing with his older brother, Ryder Robinson, 13.

SEE ALSO: Harper Beckham celebrates her birthday in princess dress at Buckingham Palace with Princess Beatrice: Pics!

The boys are all smiles as they pose next to Bing's Spider-Man-themed birthday cake.

Oh how they grow! Mr Bing Bong turned a big 6 today ❤️ #BirthdayBoy 🎂🎂🎂🎂🎂🎂

A post shared by Kate Hudson (@katehudson) on

"Oh how they grow!" Hudson captioned the picture. "Mr Bing Bong turned a big 6 today."

Hudson shares Bingham with ex-fiancé, Muse frontman Matt Bellamy, while she shares Ryder with ex Chris Robinson. She maintains a friendly relationship with Bellamy, too: Back in February, the actress took her sons to a Twenty-One Pilots concert with her ex -- more on that in the video above!

See more photos of Kate Hudson and her sons:

22 PHOTOS
Kate Hudson and her sons
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Kate Hudson and her sons
NEW YORK - NOVEMBER 26: Kate Hudson walks in SoHo with her son Ryder Russell Robinson November 26, 2004 in New York City. (Photo by Mario Magnani/Getty Images)
HONOLULU - OCTOBER 11: Actress Kate Hudson and her son Ryder Russell Robinson enjoy a preseason game between the Los Angeles Lakers and the Golden State Warriors October 11, 2005 at Stan Sheriff Center in Honolulu, Hawaii. Lakers won 101-93. NOTE TO USER: User expressly acknowledges and agrees that, by downloading and or using this photograph, User consenting to the terms and conditions of the Getty Images License Agreement. Mandatory Copyright Notice: Copyright 2005 NBAE (Photo by Andrew D. Bernstein/NBAE via Getty Images)
NEW YORK - DECEMBER 09: Actress Kate Hudson and ex husband musician Chris Robinson sighting walking with son Ryder Robinson in SOHO on December 09 2007 in New York City, New York. (Photo by Marcel Thomas/FilmMagic)
NEW YORK CITY - JUNE 18: Kate Hudson and son Ryder Russell Robinson depart their home for the airport on June 18, 2008 in New York City, New York. Kate Hudson still has wet hair after a late morning start from her dinner date the night before with Lance Armstrong at steakhouse STK. (Photos by Christopher Peterson/BuzzFoto.com) Buzz Foto LLC http://www.buzzfoto.com/ 1112 Montana Ave suite 80 Santa Monica CA 90403 1 310 441 4464 1 310 980 8822
LOS ANGELES, CA - NOVEMBER 25: Kate Hudson and her son Ryder Russell Robinson sighting on November 25, 2008 in Los Angeles, California. (Photo by COP/BuzzFoto/FilmMagic)
NEW YORK CITY - APRIL 30: (L-R) Kate Hudson and Ryder Robinson sighting at Matt Umanov Guitars (vintage guitars since 1965) in Bleecker Street on April 30, 2010 in New York City. (Photo by Christopher Peterson/BuzzFoto/FilmMagic)
NEW YORK CITY - JUNE 02: (L-R) Ryder Robinson and Kate Hudson sighting on June 2, 2010 in New York City. (Photo by Christopher Peterson/BuzzFoto/FilmMagic)
NEW YORK CITY - JUNE 05: (L-R) Kate Hudson and Ryder Robinson sighting at Cafe Gitane in Soho on June 5, 2010 in New York City. (Photo by Christopher Peterson/BuzzFoto/FilmMagic)
NEW YORK CITY - JUNE 10: (L-R) Ryder Robinson and Kate Hudson sighting at Grey Dog restaurant in Soho on June 10, 2010 in New York City. (Photo by Christopher Peterson/BuzzFoto/FilmMagic)
(EXCLUSIVE, Premium Rates Apply) (EXCLUSIVE COVERAGE) Kate Hudson and son, Ryder Robinson vacation in Punta Mita, Mexico on March 10, 2011.
PARIS, FRANCE - OCTOBER 18: Actress Kate Hudson and her sons Ryder Russell Robinson (L) and Bingham Hawn Bellamy (R) are seen arriving at aeroport de Roissy on October 18, 2012 in Paris, France. (Photo by Marc Piasecki/FilmMagic)
MIAMI, FL - FEBRUARY 27: Kate Hudson, and her sons, Bingham Hawn Bellamy and Ryder Robinson are sighted at Miami International Airport on February 27, 2013 in Miami, Florida. (Photo by Troy Rizzo/FilmMagic)
NEW YORK, NY - APRIL 17: Kate Hudson, Matthew Bellamy, Bingham Hawn Bellamy and Ryder Robinson are seen in Tribeca on April 17, 2013 in New York City. (Photo by Alo Ceballos/FilmMagic)
NEW YORK, NY - APRIL 18: Kate Hudson carries Bingham Hawn Bellamy in Tribeca on April 18, 2013 in New York City. (Photo by Josiah Kamau/BuzzFoto/FilmMagic)
NEW YORK, NY - APRIL 20: Kate Hudson and Bingham Hawn Bellamy are seen in the East Village on April 20, 2013 in New York City. (Photo by Alo Ceballos/FilmMagic)
NEW YORK, NY - APRIL 20: Kate Hudson and Bingham Hawn Bellamy are seen in the East Village on April 20, 2013 in New York City. (Photo by Alo Ceballos/FilmMagic)
LOS ANGELES, CA - JULY 30: Kate Hudson is seen at Los Angeles International Airport with her sons, Bingham Hawn Bellamy and Ryder Robinson on July 30, 2013 in Los Angeles, California. (Photo by GVK/Bauer-Griffin/GC Images)
HOLLYWOOD, CA - JANUARY 16: (L-R) Actress Kate Hudson and sons Bingham Hawn Bellamy and Ryder Robinson arrive at the Premiere of DreamWorks and Twentieth Century Fox's 'Kung Fu Panda 3' at TCL Chinese Theatre on January 16, 2016 in Hollywood, California. (Photo by Barry King/Getty Images)
HOLLYWOOD, CA - JANUARY 16: Actress Kate Hudson (R) with sons Ryder Robinson and Bingham Hawn Bellamy attend the premiere of DreamWorks Animation and Twentieth Century Fox's 'Kung Fu Panda 3' at the TCL Chinese Theatre on January 16, 2016 in Hollywood, California. (Photo by Todd Williamson/Getty Images)
NEW YORK, NY - JANUARY 25: Kate Hudson and her son Bingham Hawn Bellamy seen out and about on January 25, 2016 in New York City. (Photo by Robert Kamau/GC Images)
NEW YORK, NY - JANUARY 28: NEW YORK, NY - JANUARY 28;Actress Kate Hudson, Bingham Hawn Bellamy are seen walking in Soho on January 28, 2016 in New York City. (Photo by Raymond Hall/GC Images)
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The photo is an extremely rare instance of Hudson posting a direct image of her children. The protective mother usually covers her kids' faces with emojis when posting to social media, as to protect their privacy. While we love that Hudson tends to keep her boys anonymous, this little peak at her kids was a much-welcome surprise!

Hudson is currently dating Chief musician Danny Fujikawa. The cute couple made their first public appearance together back in May at the premiere of Hudson's mom Goldie Hawn's movie "Snatched." The pair adorably packed on the PDA for the cameras.

See photos of Kate Hudson and Danny Fujikawa at the "Snatched" premiere:

9 PHOTOS
Kate Hudson and Danny Fujikawa make red carpet debut
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Kate Hudson and Danny Fujikawa make red carpet debut
WESTWOOD, CA - MAY 10: Musician Danny Fujikawa (L) and actor Kate Hudson attend the premiere of 20th Century Fox's 'Snatched' at Regency Village Theatre on May 10, 2017 in Westwood, California. (Photo by Alberto E. Rodriguez/Getty Images)
WESTWOOD, CA - MAY 10: Actress Kate Hudson and boyfriend Danny Fujikawa arrive at the Los Angeles Premiere 'Snatched' at Regency Village Theatre on May 10, 2017 in Westwood, California. (Photo by Jon Kopaloff/FilmMagic)
WESTWOOD, CA - MAY 10: Actress Kate Hudson and boyfriend Danny Fujikawa arrive at the Los Angeles Premiere 'Snatched' at Regency Village Theatre on May 10, 2017 in Westwood, California. (Photo by Jon Kopaloff/FilmMagic)
WESTWOOD, CA - MAY 10: Actress Kate Hudson (R) and Danny Fujikawa (L) attend premiere of 20th Century Fox's' 'Snatched' at Regency Village Theatre on May 10, 2017 in Westwood, California. (Photo by Barry King/Getty Images)
WESTWOOD, CA - MAY 10: (L-R) Actress Kate Hudson and musician Danny Fujikawa attend premiere of 20th Century Fox's' 'Snatched' at Regency Village Theatre on May 10, 2017 in Westwood, California. (Photo by Barry King/Getty Images)
WESTWOOD, CA - MAY 10: Kate Hudson and Danny Fujikawa arrive at the premiere of 20th Century Fox's 'Snatched' at Regency Village Theatre on May 10, 2017 in Westwood, California. (Photo by Gregg DeGuire/WireImage)
WESTWOOD, CA - MAY 10: Kate Hudson, Danny Fujikawa arrives at the Premiere Of 20th Century Fox's 'Snatched' at Regency Village Theatre on May 10, 2017 in Westwood, California. (Photo by Steve Granitz/WireImage)
Danny Fujikawa (L) and actress Kate Hudson attend the world premiere of 'Snatched' at the Regency Village Theater, on May 10, 2017 in Westwood, California. / AFP PHOTO / VALERIE MACON (Photo credit should read VALERIE MACON/AFP/Getty Images)
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