They grow up so fast!
From the Kardashians and Jenners to the Olsen twins, there are plenty of famous siblings who’ve grown up right before our eyes!
Click through the gallery to see then-and-now photos of celebrity sisters and brothers that will make you feel old.
Demi Lovato Madison De La Garza
Demi Lovato and Madison De La Garza
Demi's little sister is now 16 years old, while the singer is 25.
Justin Bieber Jaxon Bieber
Justin and Jaxon Bieber
Justin's little brother is now eight years old, while the singer is 23.
Paris And Nicky Hilton
Nicky and Paris Hilton
Paris is now 36 and her little sis is 34.
Mary-Kate, Ashley, and Elizabeth Olsen
Mary-Kate and Ashley are 31 years old, and their baby sis is 28.
James Franco Dave Franco
James and Dave Franco
James is 39, and his little bro is 32.
Elle Fanning Dakota Fanning
Dakota and Elle Fanning
Dakota is 23, while her little sister is now 19 years old.
Britney Spears Jamie Lynn Spears
Britney and Jamie Lynn Spears
Britney's younger sister is 26 years old, while the pop star is 36.
Jaden And Willow Smith
Jaden and Willow Smith
Jaden is 19, while his sister is 17.
Kendall And Kylie Jenner
Kendall and Kylie Jenner
Kendall is 22 and her sister is 20.
Ashlee Simpson Jessica Simpson
Jessica and Ashlee Simpson
Jessica's little sister is 33 years old, while the singer is 37.
Chris Hemsworth Liam Hemsworth
Chris and Liam Hemsworth
Chris is 34 and his younger brother is 27.
Beyonce And Solange Knowles
Beyoncé and Solange Knowles
Bey's younger sister is 31 years old, while the pop star is 36.
Hilary And Haylie Duff
Haylie and Hilary Duff
Hilary's big sis is 32, while the actress is 30.
Julianne Hough Derek Hough
Derek and Julianne Hough
Derek is 32 and his sister is 29.
Kourtney, Kim, and Khloé Kardashian
Kourtney, Kim, and Khloé are 38, 37, and 33 respectively.
Vanessa Hudgens Stella Hudgens
Vanessa and Stella Hudgens
Vanessa's little sis is 22 years old, while the High School Musical actress is 29.
Luke And Owen Wilson
Owen and Luke Wilson
Owen is 49 and his brother is 46.
Tia And Tamera Mowry
Tia and Tamera Mowry
The twins are 39 years old.
Maggie And Jake Gyllenhaal
Maggie and Jake Gyllenhaal
Jake is 37 while his big sis is 40.
Miley Cyrus Noah Cyrus
Miley and Noah Cyrus
Miley is 25 and her little sis is 17.
Ali Lindsay Lohan
Lindsay and Ali Lohan
Lindsay is 31, and baby sis Ali is 24.
Kevin, Joe and Nick Jonas
Now a father of two, Kevin is 30. Joe is 28, and Nick is 25. FYI, the "bonus Jonas," baby brother Frankie, is 17!
Jack Kelly Osbourne
Kelly and Jack Osbourne.
Kelly is 33, and her brother is now 32 — and a dad to two daughters.
Nicole Sofia Richie Now Then
Nicole and Sofia Richie
Big sis Nicole is 36, while her younger sister Sofia is 19.
Taylor Austin Swift
Taylor and Austin Swift
Taylor's 28, and her younger brother, Austin, is 25.