Bruno Mars explains that smile in his mugshot
Singer Bruno Mars was arrested on September 19, 2010 in Las Vegas, Nevada, on a drug charge. He later accepted a "deferred adjudication" deal in 2011.
Stanley Kirk Burrell, aka MC Hammer, was arrested February 21, 2013, in Dublin, California, for allegedly obstructing an officer.
Actor Stephen Baldwin was arrested December 6 on a charge of failing to file New York state personal income tax returns for three years, according to a statement released by the Rockland County district attorney's office.
William J. Drayton, 53, also known as Flavor Flav, was arrested October 17 in Las Vegas and charged with assault with a deadly weapon and battery in a case involving his fiancee of eight years, police said.
Border Patrol agents in Texas arrested singer Fiona Apple on September 18, saying they found marijuana and hashish on her tour bus.
Los Angeles police took this 2011 mug shot of party girl Lindsay Lohan for violating her probation for a 2007 drunken driving conviction. She later cleaned up her act -- and the L.A. County Coroner's office -- by completing community service as a morgue janitor. 
Bad boy actor Charlie Sheen is no stranger to Hollywood scandal. He posed for this mug after a 2009 arrest related to a domestic violence dispute. 
This mug was snapped after Mel Gibson, now notorious for getting himself into trouble, was arrested and charged with drunk driving in 2006. 
Nicole Richie was sentenced to four days in jail for DUI in August 2007. She spent 82 minutes in custody. 
Musician Randy Travis was arrested August 7 for misdemeanor DWI and felony retaliation after he was involved in a one-vehicle accident and found buck naked in the roadway. He was later released on bond. 
Marshall Mathers, aka Eminem, was booked on gun charges twice in June 2000. Police said both arrests stemmed from fights -- the first over his estranged wife, Kim, and the second against rival rap group Insane Clown Posse. 
Funny-man Russell Brand landed himself in the Orleans Parish Sheriff's Office on March 16 when he snatched a photographer's iPhone and threw it at a window. Brand was free on bond after turning himsel! f in to N! ew Orleans police. 
Rapper Jay-Z was arrested in 1999 for allegedly stabbing a record executive in a New York night club. He pleaded guilty in 2001 and was sentenced to three years' probation. 
Matthew McConaughey was arrested in Austin, Texas, in 1999 after police allegedly found him dancing naked and playing bongo drums in his house. He paid a $50 fine for disturbing his neighbors with the show. 
Curtis Jackson, aka 50 Cent, posed for this mug in 1994 when he was arrested at 19 for allegedly dealing heroin and crack cocaine. 
Rob! ert Downe! y Jr.'s drug problems are almost as famous as his talent. He served time in the late 1990s on a drug conviction, was arrested in November 2000 for drug possession, and was busted again in April 2001 in Culver City, California. 
Wayne "Lil Wayne" Carter was booked on drug charges in Arizona in 2008 and sentenced to a year in prison. 
Kiefer Sutherland got this mug shot after surrendering to serve a 48-day sentence for his third DUI arrest. 
Backstreet Boy Nick Carter was arrested for drunken driving after failing a field sobriety test in 2005.
"Gossip Girl" star Chase Crawford was arrested in June 2010 in Austin, Texas, and charged with possession of marijuana. He was charged with a misdemeanor because he had less th! an 2 ounc! es, according to a police report.
Jane Fonda was arrested in Cleveland, Ohio, in 1970 after a scuffle with police in the airport. U.S. Customs agents allegedly found a large quantity of pills in her possession. 
The Oklahoma County, Oklahoma, Sheriff's office took this mug shot of the famous "Home Alone" star Macaulay Culkin after they found marijuana, Xanax and sleeping pills in his possession. He was briefly jailed before being released on bond. 
- Bruno Mars covers GQ's April Spring Bible issue
- He talks about why he smiled in his 2010 mugshot
- The singer also discusses his intent behind songwriting
(CNN) -- In the grand history of celebrity mugshots - which includes Nicole Richie's smizing and Paris Hilton's "did you get my good side?" head tilt - Bruno Mars' September 2010 photo is a standout.
The "Locked Out Of Heaven" singer had been booked on a drug charge in Las Vegas at the time. Instead of doing the stoic face of someone in trouble with the law, Mars smiled like he was at the Grammy Awards.
When GQ magazine, which hosts Mars on the cover of its April "Style Bible" issue, asked the s! inger why! he was grinning upon his arrest, Mars couldn't quite say.
"I have no idea," he responded, laughing. "It was a picture."
It's also one image that Mars would like to forget. As he told Piers Morgan last year, he's been trying to move forward ever since his arrest.
"I was really intoxicated. I was really drunk," Mars recalled to GQ. "So a lot of that is a big blur, and I try every day to forget and keep pushing."
So far, his attempt to leave the past in the past is working. Mars just notched his first No. 1 on the Billboard 200 chart with his 2012 album, "Unorthodox Jukebox" - not an easy task, he said.
"You know how hard it is to write a big song? That s*** is hard, man," he admitted to GQ. "I don't ever want to come out with something safe and get away with 'It sounds good!' It's got to be more than sounding good. The music I like are events. ... 'Bohemian Rhapsody' is my favorite song - that song's an event. And that's what I want to do. I'm sure that shocked the world, that song. 'Billie Jean' shocked the world. 'Smells Like Teen Spirit.' Those songs are events. That guy put everything he got into that, and he meant it."
But even with that intention, there are moments when Mars' own work catches him off guard.
"('Locked Out of Heaven') shocked me. That it turned out the way it did," he told the magazine. "I haven't done a song like that. And hopefully every album, I'll get that feeling. And shock the world!"
So he wants to shock the world, GQ asked?
"Hell yeah!" Mars responded. "I've got nothing else to do."