On TV: Celine Dion, Lily Allen, Justin Timberlake

Pop acts on television this week include Britney Spears and Kevin Federline’s respective exes, Jason Alexander and Shar Jackson, who appear on ‘The Dr. Keith Ablow Show’ on Monday; K.T. Tunstall, who performs on ‘The Tonight Show with Jay Leno’ on Tuesday; Lily Allen, who performs on ‘Jimmy Kimmel Live’ on Tuesday; former *NSYNC star Justin Timberlake, who performs on ‘The Victoria’s Secret Fashion Show’ on Tuesday on CBS; Drake Bell, who performs on ‘Total Request Live’ on Wednesday and ‘Late Night with Conan O’Brien’ on Wednesday; Paulina Rubio, who performs on ‘The Tonight Show’ on Wednesday; ‘American Idol’ season five champ Taylor Hicks, who visits ‘Live with Regis and Kelly’ on Wednesday; Damien Rice, who performs on ‘The Ellen DeGeneres Show’ on Wednesday; Sheryl Crow, who visits ‘The Oprah Winfrey Show’ on Thursday; and No Doubt singer Gwen Stefani, who performs on ‘Saturday Night Live’ this weekend. In addition, Monday night’s Billboard Music Awards will feature performances by Janet Jackson, Fergie, and Gwen Stefani, and appearances by the cast of ‘High School Musical’, Celine Dion, and ‘American Idol’ season five runner-up Katharine McPhee.