Kris Jenner
The victim: Kim Kardashian at Tao Nightclub at The Venetian Las Vegas to celebrate her 33rd birthday.
Cara Delevingne
The model creeped up on Sienna Miller at the Costume Institute Gala for the 'PUNK: Chaos to Couture' exhibition at the Metropolitan Museum of Art in New York City.
Simon Pegg
Pegg pranked co-stars Paula Patton, Tom Cruise and Léa Seydoux at the Mission: Impossible - Ghost Protocol premiere in London.
Adam Lambert
The singer snuck into fans' selfie during the 19th Annual Miami Make-A-Wish Ball at the InterContinental Hotel in Miami, Fla.
Jennifer Lawrence
The victims: Liam Hemsworth, Elizabeth Banks, Nina Jacobson and Jena Malone, attending a special screening of The Hunger Games: Catching Fire in New York City.
Christina Applegate
The victim: Leslie Mann, attending the premiere of Anchorman 2: The Legend Continues in London.
Hayden Panettiere
Frédéric Prinz von Anhalt got photobombed by the Nashville star at the 71st Annual Golden Globe Awards in Beverly Hills.
George Clooney
Clooney tried to steal the spotlight from Steven Spielberg, Jessica Seinfeld and Jerry Seinfeld at the USC Shoah Foundation Institute 2013 Ambassadors for Humanity gala in New York City.
Amber Tamblyn
The actress teased her husband David Cross and pal Amy Poehler at the Sleep No More New Year's Eve 2014 Party in New York City.
Zach Braff
Only in the Big Apple! The Scrubs actor photobombed a random newlywed couple in the streets of NYC, as captured by professional shutterbug Sascha Reinking.
Jane Fonda, Melanie Griffith and Carly Simon
The Newsroom star has mastered the art of photobombing.
Aaron Paul and Bryan Cranston
One week before the Breaking Bad series finale aired, the two costars tried to lighten the mood with their hilarious antics on the red carpet.
Demi Lovato and Nick Jonas
Step aside Joe Jonas! The youngest Jo Bro reunited with his close friend at the Teen Choice Awards in Los Angeles. But Joe just had to get in the middle of things.
Rebel Wilson
Shortly after winning a Teen Choice Award, the Pitch Perfect star unknowingly posed with costars Anna Camp and Skylar Astin.
Queen Elizabeth II
Her Majesty was upstaged by Princess Eugenie at day one of the Royal Ascot races.
Joshua Jackson
The victim: The Dawson's Creek star made a wide-eyed expression behind Anne Hathaway while walking the 2013 Met Gala red carpet.
Emma Stone
With the help of James Corden, Stone photobombed her then-boyfriend Andrew Garfield, Eleanor Matsuura and Neil Stuke.
Justin Bieber
The victims: Katy Perry and then-husband Russell Brand.
Kelly Clarkson
The victims: Ellen DeGeneres and wife Portia de Rossi.
Russell Brand
The Victims: Actors Robert Pattinson, Cam Gigandet, Taylor Lautner and Kristen Stewart on stage at the 2008 MTV Video Music Awards.
Neil Patrick Harris
The victims: Ian Somerhalder and his very attractive friend.
Michael Cera
The victims: Whoever these people are.
Ringo Starr
The Victims: Justin Bieber and Ke$ha during dress rehearsal at Staples Center.
Jake Gyllenhaal
The victims: Brokeback Mountain director Ang Lee and Uma Thurman.