On TV: Nick Lachey, Jessica Simpson, Ben Jelen

Pop acts on television include Jessica Simpson and Nick Lachey of 98 Degrees, who appear together on ‘The Late Show with David Letterman’ on Monday and ‘The Ellen DeGeneres Show’ on Friday, while Nick appears alone on ‘Live with Regis and Kelly’ on Tuesday; ‘American Idol’ reject turned cult hero William Hung, who performs on ‘The Tonight Show’ with Jay Leno on Thursday and ‘Today’ on Friday; Ben Jelen, who performs on ‘Last Call with Carson Daly’ on Thursday; the eliminated ‘American Idol’ contestant appears on ‘On Air with Ryan Seacrest’ on Thursday; and Abra Moore, who performs on ‘Live with Regis and Kelly’ on Friday.