Celebrity·Posted on Jan 9, 201821 Side-By-Sides Of Celebrity Best Friends Then Vs. NowThe very definition of a glow-up.by Nora DominickBuzzFeed StaffFacebookPinterestTwitterMailLink 1. Leonardo DiCaprio and Kate Winslet Hal Garb / AFP / Getty Images, Christopher Polk / Getty Images Ever since starring in Titanic together 20 years ago, the duo have remained extremely close friends. They are even known to go out to dinner with each other and take vacations together, and Kate was also there to support Leo when he finally won an Oscar in 2016. 2. Busy Philipps and Michelle Williams Instagram: @busyphilipps / Via instagram.com, Pascal Le Segretain / Getty Images The duo met when Busy joined Michelle on Dawson's Creek in 1998 and they've been best friends ever since. 3. Demi Lovato and Nick Jonas Gareth Cattermole / Getty Images, Valerie Macon / AFP / Getty Images The duo became friends on the set of Camp Rock in 2008. And in 2016 they headlined a tour together. 4. Sophie Turner and Maisie Williams Tim P. Whitby / Getty Images, Instagram: @maisie_williams / Via instagram.com The duo met when they were both cast on Game of Thrones in 2011 and have been inseparable ever since. They even have a couple name: #mophie. 5. Vanessa Hudgens and Ashley Tisdale Mark Mainz / Getty Images, YouTube / Ashley Tisdale / Via youtube.com The duo met on the set of High School Musical in 2006. Last year they reunited and sang a cover of "Ex's and Oh's." 6. Harry Styles and James Corden YouTube / Sky One / Via youtube.com, YouTube / CBS / Via youtube.com The duo have been smitten with each other for years now. James helped write One Direction's "Best Song Ever" music video in 2013. In 2017, their bromance reached a new level when Harry was the musical guest on The Late Late Show for an entire week. 7. John Stamos and Lori Loughlin Instagram: @johnstamos / Via instagram.com, Instagram: @loriloughlin / Via instagram.com Since playing Jessie and Rebecca on Full House from 1987–1995, John and Lori have stayed very close. You can now catch them posting adorable selfies behind the scenes of Fuller House. 8. Justin Timberlake and Jimmy Fallon Frank Micelotta / Getty Images, Larry Busacca / Getty Images The duo became best friends after starring in an SNL sketch together in the early 2000s. Now, Justin is a frequent guest on The Tonight Show With Jimmy Fallon. 9. Tina Fey and Amy Poehler Evan Agostini / Getty Images, Kevork Djansezian / Getty Images Tina and Amy met in 1993 at Chicago's ImprovOlympics and have been the queens of comedy ever since. From hosting SNL's Weekend Update together to working on films like Sisters in 2015, Tina and Amy are the best of friends. 10. Penélope Cruz and Salma Hayek Lucy Nicholson / AFP / Getty Images, Kevin Winter / Getty Images Penélope and Salma have been BFFs for over 20 years. From Penélope pranking Salma on Punk'd in 2005 to endless selfies together, they are true BFF goals. 11. Lea Michele and Jonathan Groff Playbill / Via playbill.com, Instagram: @leamichele / Via instagram.com From the original Broadway production of Spring Awakening in 2006 to Glee to constant reunions in NYC, Lea and Jonathan are the definition of BFFs. 12. Mindy Kaling and B.J. Novak Evan Agostini / Getty Images, Pascal Le Segretain / Getty Images The duo wrote and starred in The Office together from 2005–2013. You can see them frequently comment on each other's Instagram posts and B.J. even guest-starred on The Mindy Project. 13. Oprah Winfrey and Gayle King Oprah Winfrey Show / King World Productions / Via oprah.com, Ilya S. Savenok / Getty Images When you say BFF, you think of Oprah and Gayle. The duo have been best friends for over 40 years and continue to support each other no matter what. 14. Selena Gomez and Taylor Swift Frazer Harrison / Getty Images, Valerie Macon / AFP / Getty Images The duo met when they were both dating two of the Jonas brothers back in 2008. Recently, Selena posted an adorable video for Taylor's 28th birthday. 15. Adam Sandler and Drew Barrymore Frank Micelotta / Getty Images, Alberto E. Rodriguez / Getty Images The duo starred in The Wedding Singer together in 1998. The duo, which starred in The Wedding Singer together in 1998, most recently starred in the comedy Blended in 2014. 16. Jennifer Aniston and Courtney Cox Dan Callister / Getty Images, Angela Weiss / Getty Images The two met on the set of Friends in 1994. Jennifer even guest-starred on Courtney's show Cougar Town in 2010. 17. Naomi Watts and Nicole Kidman Vince Bucci / Getty Images, Dimitrios Kambouris / Getty Images The duo became BFFs on set of the 1991 film Flirting. Now you can frequently spot them being each other's plus-ones to numerous Hollywood parties and movie premieres. 18. Brad Pitt and George Clooney Gerard Julien / AFP / Getty Images, Kevin Winter / Getty Images Brad and George have been good friends for over 20 years now and man, have they aged well. Not only have they starred together in films like Ocean's Eleven in 2001, but they even have a long-standing prank war. 19. Ashley Benson and Shay Mitchell Frazer Harrison / Getty Images, Instagram: @ashleybenson / Via instagram.com The duo met on the set of Pretty Little Liars in 2010 and now they're inseparable. In December 2017, they reunited for an end-of-year wine and cheese night. 20. Mariska Hargitay and Debra Messing Alberto E. Rodriguez / Getty Images, Instagram: @debramessing / Via instagram.com The duo have been extremely close for years, and their adorable Instagram selfies are proof their friendship is still going strong. Whether they're brunching in NYC or exploring LA, they're the perfect BFFs. 21. And finally, Alexis Bledel, America Ferrera, Blake Lively, and Amber Tamblyn Matthew Simmons / Getty Images, Instagram: @americaferrera / Via instagram.com The foursome met on the set of Sisterhood of the Traveling Pants in 2005. They all recently reunited to celebrate America Ferrera's pregnancy.