Celebrities are often spotted cuddling - lodged in a tongue-in-tongue steamy lip-lock, both onscreen and in public.

Amusingly, PDA is quite ordinary among celebs, be it a chick-on-chick or man-on-man encounter. Well, it is not something apparent; stars are often spotted sharing an out-of-control smacker during performances, award functions and fashion events.

Recently, actor Ryan Gosling was caught kissing director Nicolas Winding Refn while walking the Cannes red carpet.

Interestingly, now Meryl Streep and Sandra Bullock are also added in the huge list of celebrities who were jammed in a steamy girl-on-girl lip-lock both on and off the stage.

Other celebs who were seen puckered up, sharing a hot lip-lock with girls include Madonna and Britney Spears, Lindsay Lohan and Samantha Ronson, Madonna and Gwyneth Paltrow, Jennifer Aniston and Courteney Cox, Denise Richards and Neve Campbell, Sarah Michelle Gellar and Selma Blair, and the trio of Cristina Barcelona, Penelope Cruz and Scarlett Johansson.

Scroll down and check out top 20 sizzling celebrity kisses caught on camera.

Britain's Prince William and his wife Catherine, Duchess of Cambridge, kiss as they stand next to bridesmaids Grace van Cutsem (L) and Margarita Armstrong-Jones (R) on the balcony at Buckingham Palace with other members of the Royal Family, after their wedding in Westminster Abbey, in central London April 29, 2011. Image Credit: Reuters

Singer Lady Gaga and New York City Mayor Michael Bloomberg kiss each other during celebrations at the New Year Eve ball in Times Square in New York, January 1, 2012. Image Credit: Reuters

Britney Spears (L) gets a kiss on the mouth from Madonna during the opening act of the 2003 MTV Video Music Awards at the Radio City Music Hall in New York, August 28, 2003. Image Credit: Reuters

Actors Angelina Jolie and Brad Pitt kiss at their table during the 14th annual Screen Actors Guild Awards in Los Angeles January 27, 2008. Image Credit: Reuters

Singer Katy Perry and husband British actor Russell Brand kiss on the red carpet as they arrive at the 53rd annual Grammy Awards in Los Angeles, California February 13, 2011. Image Credit: Reuters

Model Heidi Klum and singer Seal kiss on the red carpet at the 52nd annual Grammy Awards in Los Angeles January 31, 2010. Image Credit: Reuters

Singer Mariah Carey (L) is kissed by her husband Nick Cannon as Oprah Winfrey looks on while appearing on the Oprah television show being broadcast from New York's Central Park, September 18, 2009. Image Credit: Reuters

Jada Pinkett-Smith (L) kisses her husband Will Smith as the Los Angeles Lakers play the Boston Celtics in Game 4 of the NBA Finals basketball championship in Los Angeles June 12, 2008. Image Credit: Reuters

Maroon 5 singer Adam Levine (L) kisses model Anne Vyalitsyna during the kiss cam in a time out of the NBA basketball game between the Los Angeles Lakers and the Chicago Bulls in Los Angeles December 25, 2011. Image Credit: Reuters

Jennifer Lopez and her husband Marc Anthony kiss at the conclusion of their performance at the Carousel of Hope Ball in Beverly Hills, California October 23, 2010. Image Credit: Reuters

Actress Sarah Jessica Parker kisses her husband, actor Mathew Broderick, before the 82nd Academy Awards in Hollywood March 7, 2010. Image Credit: Reuters

Actress Meryl Streep (L) and Sandra Bullock kiss after their tie win for best actress at the 15th Critics' Choice Movie Awards at the Hollywood Palladium in Los Angeles January 15, 2010. Image Credit: Reuters

Canadian country singer Shania Twain kisses her husband Frederic Nicolas Thiebaud after unveiling her star on the Walk of Fame in Hollywood, California June 2, 2011. Image Credit: Reuters

British singer Paul McCartney kisses his wife Nancy Shevell before unveiling his star on the Walk of Fame in Hollywood, California February 9, 2012. Image Credit: Reuters

U.S. President Barack Obama kisses first lady Michelle as they dance at the Eastern Regional Inaugural Ball in Washington January 20, 2009. Image Credit: Reuters

France's President Nicolas Sarkozy (L) kisses first lady Carla Bruni-Sarkozy as they leave the Elysee Palace for the president to vote in the second round municipal elections in Paris on March 16, 2008. Image Credit: Reuters

Newly-weds Prince Albert II of Monaco and Princess Charlene kiss on the Palace balcony after the civil wedding service in Monaco July 1, 2011. Image Credit: Reuters

Socialite Paris Hilton and her friend Doug Reinhardt kiss as they arrive on the red carpet for the screening of the film Inglourious Basterds by director Quentin Tarantino at the 62nd Cannes Film Festival May 20, 2009. Image Credit: Reuters