Celebrities caught off guard

Singer Katy Perry arrives at the premiere of "Katy Perry: Part of Me" held at Grauman's Chinese Theater on June 26, 2012, in Hollywood, Calif.

Rihanna performs onstage during Fox's "American Idol 2012" results show at the Nokia Theater on May 23, 2012, in Los Angeles.

Singer Chris Brown attends Game Four of the 2009 NBA Finals between the Los Angeles Lakers and the Orlando Magic on June 11, 2009, at Amway Arena in Orlando, Fla.

Host Hayley McQueen attends the European premiere of "Katy Perry: Part of Me" at Empire Leicester Square on July 3, 2012, in London.

Robert Pattinson arrives at the "Water for Elephants" premiere at the State Theatre on May 6, 2011, in Sydney, Australia.

Rapper Lil Wayne watches as Floyd Mayweather Jr. takes on Miguel Cotto in their WBA super welterweight title fight at the MGM Grand Garden Arena on May 5, 2012, in Las Vegas.

Kim Kardashian serves gravy for mashed potatoes as the homeless and those less fortunate enjoy a meal at the Los Angeles Mission on Nov. 23, 2011, in downtown Los Angeles in celebration of Thanksgiving.

Miley Cyrus yawns during an earlier morning appearance at the 16th annual EIF Revlon Run/Walk for Women on May 9, 2009, in Los Angeles.

Selena Gomez visits radio host Elvis Duran on April 26, 2012, in Los Angeles.

Actress Blake Lively appears onstage during MTV's "Total Request Live" at the MTV Times Square Studios on Oct. 1, 2007, in New York.

Actor Taylor Lautner arrives at the "Abduction" Sydney premiere at Hoyts Cinemas on Aug. 23, 2011, in Sydney, Australia.

Natalie Portman reacts as she arrives on the red carpet for the 83rd Annual Academy Awards held at the Kodak Theatre on Feb. 27, 2011, in Hollywood, Calif.

Britney Spears holds her Best Pop Video Award and her Michael Jackson Video Vanguard Award in the press room at the 2011 MTV Video Music Awards, Aug. 28, 2011, at the Nokia Theater in downtown Los Angeles.

Singer Carly Rae Jepsen arrives at the Los Angeles premiere "Katy Perry: Part Of Me" at Grauman's Chinese Theatre on June 26, 2012, in Hollywood, Calif.

Singer Reece Mastin arrives at the "Katy Perry: Part Of Me" Australian premiere on June 30, 2012, in Sydney, Australia.

Comedian Russell Brand speaks during the FX portion of the 2012 Winter TCA Press Tour at The Langham Huntington Hotel and Spa on Jan. 15, 2012, in Pasadena, Calif.

Actor Ryan Gosling attends the "Drive" premiere during the 64th Annual Cannes Film Festival at Palais des Festivals on May 20, 2011, in Cannes, France.

Sharon Stone and Robert Pattinson attend the amfAR Cinema Against AIDS 2009 show during the 62nd annual Cannes Film Festival on May 21, 2009, in Antibes, France.

Justin Bieber attends the Tribeca Disruptive Innovation Awards during the 2012 Tribeca Film Festival at the NYU Paulson Auditorium on April 27, 2012, in New York.

Miley Cyrus attends the premiere of Disney's ''Hannah Montana & Miley Cyrus: Best of Both Worlds Concert'' at the El Capitan Theatre on Jan. 17, 2008, in Hollywood, Calif.

Robert Pattinson poses during the "Cosmopolis" premiere at Le Grand Rex on May 30, 2012, in Paris, France.

Lady Gaga waves to fans as she leaves the airport following her arrival in Bangkok on May 23, 2012.

Katie Holmes arrives at the opening night of "Beauty Culture" at the Annenberg Space for Photography on May 19, 2011, in Los Angeles.

Lindsay Lohan listens during her arraignment after being charged with one count of felony grand theft for allegedly stealing a $2,500 necklace from a Venice Beach jewelry store, at the Airport Superior Court on Feb. 9, 2011.

Taylor Swift accepts the Entertainer of the Year Award onstage at the 47th Annual Academy Of Country Music Awards on April 1, 2012, in Las Vegas.

Talk show host Rikki Lake arrives at the opening of "Mamma Mia!" on April 25, 2004, at the Pantages Theatre in Hollywood, Calif.

Singer and actress Jennifer Lopez is seen during a press conference at the Hospital del Nino (Children's Hospital) in Panama City on June 12, 2012.

Actress Blake Lively accepts the Breakthrough Performer of the Year award at the CinemaCon awards ceremony at Caesars Palace during CinemaCon, March 31, 2011, in Las Vegas.

Kanye West puts his arm around Kim Kardashian from their courtside seats as the Los Angeles Lakers take on the Denver Nuggets in game seven of the Western Conference Quarterfinals in the 2012 NBA Playoffs on May 12, 2012, in Los Angeles.