Julianne Moore was full of holiday spirit at a NY Knicks game on Christmas Day in 2011.

Eva Longoria [6] sat courtside with Kevin Costner [7] and her stylist, Robert Verdi, while watching the NY Knicks play the Dallas Mavericks in February 2012.

Tobey Maguire [8] couldn't stay in his seat during an LA Lakers game in November 2003.

Ryan Phillippe [9] and David Spencer cheered on the NY Knicks as they played the Washington Wizards in April 2013.

Justin Long [10] had a hard time dealing with a play during an NY Knicks game with his brother, Christian, in April 2015.

Kaley Cuoco put her fingers up while sitting courtside with her dad, Gary, at an LA Lakers game in January 2016.

Double high-five! Ben Stiller [11] and Jason Sudeikis shared an enthusiastic moment as the NY Knicks played the Boston Celtics in May 2013.

Chrissy Teigen was overcome with emotion while at an LA Clippers game with husband John Legend [12] in April 2014.

Jay Z and Beyoncé Knowles [13] cheered on the Brooklyn Nets as they played the Toronto Raptors in November 2012.

NY Rangers fan Tom Hanks [14] rooted for the team at a game in February 2015.

Mila Kunis [15] looked outraged by a play during an LA Lakers game with Ashton Kutcher [16] in February 2013.

Rihanna [17] was about to stand up and coach the LA Clippers herself during a playoff game in May 2014.

Joel McHale was very confused while watching the Lakers play in November 2013.

Legendary Knicks fan Spike Lee did a celebratory dance while courtside in May 2013.

Katie Holmes [18] couldn't contain her excitement after a big moment in the Miami Heat vs. New York Knicks game in January 2014.

Vanessa Hudgens [19] and Josh Hutcherson cheered on the LA Lakers as they played the New Orleans Hornets in March 2011.

Kate Middleton had a look of shock on her face while watching a match during Wimbledon in July 2014.

Ashley and Mary-Kate Olsen [20] sported shades and smiles during a NY Knicks game in May 2013.

Boston native Maria Menounos cheered on her hometown team, the Celtics, in February 2013.

Margot Robbie couldn't hold in her excitement while watching the New York Rangers game [21] with her boyfriend, Tom Ackerley, in February 2015.

David Beckham [22] gave his son Cruz an adorable high five as they watched the Lakers play together in April 2012.

Conan O'Brien [23] and his family couldn't contain their excitement while watching the LA Clippers play in January 2016.

Cuba Gooding Jr. looked like a vein was about to pop out of his head as he screamed during a NY Rangers playoff game in April 2014.

Reese Witherspoon [24] and husband Jim Toth had major reactions to a play during an LA Lakers game in March 2013.

Noted Knicks fan Emmy Rossum had a full range of emotions while watching the team play in March 2015.

Donnie Wahlberg expressed himself while watching the Boston Celtics take on the Chicago Bulls in a May 2009 finals game.

Ty Burrell made a choking motion while watching a tense game between the San Antonio Spurs and LA Clippers in November 2014.

Olivia Wilde [25] and Jason Sudeikis had serious game faces on during a Lakers game in November 2013.

Jay Z shared an adorable moment with his godson at a Brooklyn Nets game in April 2013 — their mutual excitement made for one sweet photo!

This was Gwen Stefani [26]'s reaction during a US Open tennis match in September 2014.

Taylor Swift [27]'s signature surprised face took on a different tone as she sat courtside for a Knicks game in November 2014.

Drake couldn't stay in his damn seat while watching his beloved Toronto Raptors play the Houston Rockets in March 2016.

Jason Bateman [28] was all riled up while watching an LA Dodgers game in October 2013.

Prince Harry raised his arms over his read during the Rugby World Cup in September 2015.

Khloé Kardashian cheered on her then-husband, Lamar Odom, during an LA Clippers game in April 2013.

Ashton Kutcher [29] and Kaley Cuoco got excited during a November 2012 Lakers game.

Joseph Gordon-Levitt cheered on the LA Lakers with his dad, Dennis, in January 2013.

Miley Cyrus [30] and her sister Brandi had pained expressions while watching the Knicks play the Cleveland Cavaliers in March 2016.

Prince William and Kate Middleton had royally hilarious reactions to a hockey match in Scotland back in July 2014.

Saturday Night Live [31] star Cecily Strong and Veep's Sam Richardson were so bummed out by the NY Knicks that they couldn't even look at the game anymore.

Justin Timberlake [32] stood up and cheered while checking out an NBA Playoffs game between the LA Lakers and Denver Nuggets with Jessica Biel [33] in May 2012.

Amy Schumer and Dianna Agron [34] were both perplexed by a play at an LA Lakers game in March 2014.

Usher [35] celebrated as the Cleveland Cavaliers defeated the Orlando Magic during the NBA playoffs in May 2009.

Kelly Rowland [36] cheered on her friend Serena Williams during her US Open match in September 2015.

Ansel Elgort was a one-man cheering section at a January 2015 Knicks game — he also had more hilarious moments courtside [37].

Chloë Grace Moretz looked superstressed during an NBA playoff game between the Oklahoma City Thunder and LA Clippers in May 2014.

Kim Sears was almost completely blown away while cheering on her now-husband, Andy Murray, during the Australian Open in January 2015.

Things got serious for Mark Wahlberg [38] and Matt Damon [39] as they watched their hometown team, the Boston Celtics, play in the NBA Finals in June 2008.

When she wasn't showing sweet PDA with boyfriend Cody Simpson [40], Gigi Hadid dramatically cheered on the NY Knicks during a game in April 2015.

Drake looked like he was having an out-of-body experience while watching his hometown team, the Toronto Raptors, take on the LA Lakers in November 2014.

Selena Gomez [41] had a look of worry while watching the Lakers play with then-boyfriend Justin Bieber in April 2012.

Sophia Bush had a winning smile during a Lakers game in April 2012.

Christie Brinkley was adorably animated while watching the NY Knicks play the Golden State Warriors in February 2015.

Jack Black [42] showed unstoppable energy while watching the LA Lakers in January 2016.