Above, boy band Big Time Rush is caught in their underwear while filming a scene for an upcoming scene in their Nickelodeon TV series. The shot is from Tiger Beat (October 2012), but the boys are all of age and then some. (From L to R: James Maslow, 22; Logan Henderson, 23 today!; Kendall Schmidt, 21; and Carlos Pena, 23.) Below, Twist (September 2012) offers Niall Horan, 19 as of yesterday, of One Direction:

Okay, enough kid stuff. Check out manly Michael Phelps from OK! (September 24, 2012):

More after the jump...