Who knew Jennifer Love Hewitt could sing? The former “Party of Five” star makes her television musical debut on “The Teen Choice Awards” (7 p.m., Fox). Other pop performers include Nelly and BBMak. Teen voters have chosen the most notable teenage personalities from the worlds of film, television, music, fashion and sports. Actress Reese Witherspoon (“Legally Blonde”) is also scheduled to appear and will be honored with the Extraordinary Achievement Award.

Additional celebrities scheduled to appear include Bernie Mac, Matthew Perry and Matt LeBlanc, Frankie Muniz, Sarah Michelle Gellar and Jack and Kelly Osbourne.

“Mystery” takes a new direction with “The Inspector Lynley Mysteries: A Great Deliverance” (8 p.m., PBS, check local listings, part one of two). While the “Lynley” novels are set in the British countryside and feature all of the cozy and quirky attributes of English whodunits, they are based on the best-selling novels by Elizabeth George, a former American teacher who makes her home in California, thousands of miles from England’s green and pleasant land.

Nathaniel Parker stars as Inspector Lynley of Scotland Yard. He’s a dedicated sleuth who happens to be a high-born aristocrat, the eighth Earl of Asherton. He’s assigned to investigate a grisly decapitation in Yorkshire barn. Sharon Small plays his no-nonsense working-class assistant Sgt. Barbara Havers, who bristles at her new partner and calls him an “arrogant aristocratic ponce.”

But events in Yorkshire leave little time for class warfare. The decapitated victim left a secret fianc a runaway wife and daughter, an angry nephew and many other loose threads. The local police force resents Scotland Yard’s intrusion, and several on the force have a personal vendetta against Lynley. The growing trail of evidence, not too mention the thick Yorkshire accents of many of the witnesses and suspects, may leave some viewers baffled. The fact that neither Lynley nor Havers emerges as an entirely likable character also detracts from this challenging mystery.

The Academy Award winning documentary short “Thoth” (6 p.m., Cinemax) profiles a startling New York City street musician who accompanies his five-octave vocal range with a classical violin. Outfitted in an Indian headdress, chains and a loincloth, Thoth performs dressed one-man operas based entirely on his own personal mythology. Thoth and “Thoth” are strange, compelling and utterly original.

The “Investigative Reports” film “The Patriot and the Taliban” (8 p.m., A&E) looks at the fateful meeting between “American Taliban” John Walker Lindh and the CIA special agent Mike Spann, who interrogated Lindh only moments before dying in a Taliban prison revolt on Nov. 25, 2001.

Tonight’s other highlights

Denver meets San Francisco in NFL pre-season action on “Monday Night Football” (7 p.m., ABC).

l The cable family series “State of Grace” (7 p.m., ABC Family) concludes its second season with two original half-hour episodes.

Mia Farrow and Julia Whelan (“Once and Again”) star in the 2002 drama “The Secret Life of Zoey” (7 p.m., Lifetime) about a family’s anguish over a teenager’s hidden drug addiction.

A bookstore owner meets her demise on a repeat of “CSI” (9 p.m., CBS).

Three female suitors compete on “Meet My Folks” (9 p.m., NBC).

Series notes

“Dog” is new … Doug cringes at Carrie’s new hair-do on “King of Queens” (7 p.m., CBS) … Joe Rogan hosts “Fear Factor” (7 p.m., NBC) … Oglevee recalls a student uprising on “The Parkers” (7 p.m., UPN) … Mary and Lucy go to New York on “7th Heaven” (7 p.m., WB) A trying Christmas on “Yes, Dear” (7:30 p.m., CBS).