 In 2012, Mars was named 2011's best selling music artist worldwide.After he signed with Atlantic Records in 2009, he composed (as part of production group The Smeezingtons) and sang guest vocals on the debut singles of American rappers B.o.B ("Nothin' on You") (2009) and Travie McCoy ("Billionaire") (2010).The former single peaked at number one on the US "Billboard" Hot 100, in the Netherlands and in the United Kingdom, the latter also topped the Netherlands' singles chart.