Actors are often known for their on-screen romantic and passionate kisses. However, off-screen, kissing can be an awkward business even if the person is a celebrity.

Author Rene Yasenek once said that kissing is a means of getting two people so close together that they can't see anything wrong with each other.

From Angelina Jolie to Kate Winslet and even Barack Obama, let's take a look at some of the famous celebrity kisses of all times.

Included in our list of famous celebrity lip-locks is the brief kiss between Prince William and Kate Middleton that took place on the Buckingham Palace balcony on the occasion of the royal wedding. The kiss sparked cheers from the already ecstatic crowds, and was repeated during the flypast.

For many of the hundreds of thousands of well-wishers gathered below the famous balcony, the kiss was the royal wedding moment they were waiting for.

Another famous kiss is the one between President Obama and the First Lady Michelle as they dance at the Eastern Regional Inaugural Ball in Washington on Jan 20, 2009.

Start the slideshow to take a look at some of the famous pictures of celebrities kissing:

Angelina Jolie
Angelina Jolie and Brad Pitt Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
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. Reuters
Nicole Kidman and Keith Urban
Nicole said in another interview that she enjoys living close to her present husband Keith Urban, even if it's in a farm. Reuters
Kate Middleton Prince William wedding
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. Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
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. Reuters
Genoa Bridge Collapse Dozens Dead As Desperate Search For Survivors Goes On
Genoa Bridge Collapse: Dozens Dead As Desperate Search For Survivors Goes On
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
BET honoree musician Mariah Carey kisses her husband Nick Cannon and their son Moroccan Scott Cannon at the BET Honors in Washington January 14, 2012. Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
Singer Kirk Franklin kisses his wife Tammy as he holds his awards for "Best Gospel Album" and Best Gospel Song (Hello Fear) at the 54th annual Grammy Awards in Los Angeles, California, February 12, 2012. Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
Actress Kate Winslet holds her awards for Best Actress in a Motion Picture Drama for "Revolutionary Road" and Best Supporting Actress in a Motion Picture for "The Reader'' as her husband-director Sam Mendes kisses her at the 66th annual Golden Globe awards in Beverly Hills, California January 11, 2009. Mendes directed "Revolutionary Road". Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
U.S. President Barack Obama kisses first lady Michelle as they dance at the Eastern Regional Inaugural Ball in Washington January 20, 2009. Obama took power as the first black U.S. president on Tuesday and quickly turned the page on the Bush years, urging Americans to rally to end the worst economic crisis in generations and repair the U.S. image abroad. Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
Model Heidi Klum and singer Seal kiss on the red carpet at the 52nd annual Grammy Awards in Los Angeles January 31, 2010. Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
US actor Michael Douglas kisses his fiancee Welsh actress Catherine Zeta-Jones after the opening of the actor's new cultural center in the village of Valldemossa on the Spanish island of Mallorca March 25, 2000. Douglas, 56, and Zeta-Jones, 31, were married in a lavish ceremony in Manhattan's Plaza Hotel on November 18. Reuters
From Angelina Jolie to Kate Middleton Most Famous Celebrity Kisses of All Times
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. The ball benefits The Barbara Davis Center for Childhood Diabetes. Reuters
Barack obama Royal wedding Kate middleton Barack obama