On TV: Kelly Clarkson, Gwen Stefani, Clay Aiken

Pop acts on television this week include No Doubt singer Gwen Stefani, who performs on ‘The Late Show with David Letterman’ on Monday and visits ‘Total Request Live’ on Tuesday; Tegan & Sara, who visit ‘Jimmy Kimmel Live’ on Wednesday; ‘American Idol’ season two runner-up Clay Aiken, who appears on ‘Live with Regis and Kelly’ on Thursday; ‘American Idol’ season one champ Kelly Clarkson, who performs on ‘Last Call with Carson Daly’ on Friday; and ‘Newlyweds’ stars Nick Lachey and Jessica Simpson, who visit ‘The Tonight Show with Jay Leno’ on Friday.