Derek Hough, Jonah Hill, Jerry O'Connell and Josh Groban will serve as guest co-hosts opposite Kelly Ripa on 'Live! With Kelly.'

O'Connell will appear this Friday, Nov. 25. Guests include Jane Lynch and Nathan Fillion. O'Connell has guest hosted with Ripa in the past.

Hough, who lost 'Dancing With the Stars' to Karina Smirnoff and J.R. Martinez, will serve as co-host on Mon., Dec. 5. He'll interview Paula Dee, Elizabeth Olsen and Jeffrey Donovan with Ripa. Hill will guest co-host on Tues., Dec. 6 and interview Sarah Jessica Parker, Emily VanCamp and Richard Blais. This is the first time Hough and Hill will serve as guest co-hosts.

The stars are lining up to say goodbye to Regis Philbin.

The 80-year-old entertainer is leaving 'Live! With Regis and Kelly' on Fri., Nov. 18, but not before some old friends -- including former 'Live!' co-host Kathie Lee Gifford -- return to pay tribute to the talk show host.

Gifford will appear on Thurs., Nov. 17, Philbin's second-to-last show. Additional guests include: Don Rickles (Nov. 14), Jimmy Fallon (Nov. 14), Donald Trump (Nov. 15) and David Letterman (Nov. 16).

Singers Tony Bennett, Bret Michaels and Josh Groban will also stop by for special musical performances.

With Andy stepping up as the new regional manager on 'The Office' (Thu., 9PM ET on NBC), we're getting the opportunity to get deeper into him as a character. This week, that was through a garden party he threw -- at Schrute Farms! -- to try and make his father proud of him.

Stephen Collins and Dee Wallace played his parents, joined by Josh Groban as his younger, and clearly favored brother. He even got the namesake from the father, rather than the eldest son! It became a lot more clear why Andy's so insecure and acts out ... and even had such rage issues when we first met him.

Katie Couric will join Kelly Ripa at the hosting table of 'Live! With Regis and Kelly' on Tues., Oct. 11.

The new ABC star will help Ripa interview Dylan McDermott and Anna Torv in addition to sharing her mom's pear and jello recipe during the 'Live' "Co-Host Cook-Off Week" segment.

Other upcoming 'Live' co-hosts include:
• Carson Kressley (Oct. 7)
• Michael Strahan (Oct. 12)
• Jerry O'Connell (Oct.13)
• Mark Feuerstein (Oct. 14)
• Josh Groban (Oct. 21)
• Nick Lachey (Oct. 31)

Yep, Regis won't be there for the show's famous Halloween spectacular.

In other casting news ...

While some shows have lured famous movie stars into leading roles, other shows are taking a more temporary approach this fall with big-name guest stars booked for short-term stints on the small screen.

Fall TV will host several major reunions that you definitely won't want to miss. Terry O'Quinn will head back to the island for a stint alongside former 'Lost' costar Daniel Dae Kim on 'Hawaii Five-0,' while Ray and Debra are back together (sort of) when Ray Romano stops by 'The Middle' to visit his former 'Everybody Loves Raymond' costar Patricia Heaton. And let's not forget 'Buffy the Vampire Slayer' alums Charisma Carpenter and James Marsters playing a married couple on an episode of 'Supernatural' this season.

Wanna know who else is heading to TV this fall? Check out some more of the biggest and best guest stars, including 'The Wire' alum Michael K. Williams (Omar!), Oscar-nominated actress Patricia Clarkson and crooner Josh Groban in AOL TV's fall guest star gallery.

The angel sent from heaven to deliver platinum records unto us known as Josh Groban ("Who is Josh Groban?! Kill yourself!") is branching out into acting even more.

The multi-platinum singer, who recently co-starred in 'Crazy, Stupid, Love,' will travel to Scranton for a guest spot on 'The Office' as Andy Bernard's brother, Deadline reports. Sadly, his 'CSL' co-star Steve Carell won't be there anymore.

He'll join former '7th Heaven' reverend Stephen Collins and 'ET''s Dee Wallace, who were just cast as Andy's parents.

In other TV casting news ...

Josh Groban, who was filling in for Regis Philbin on 'Live With Regis and Kelly' (weekdays, syndicated), found himself getting harassed by Kirstie Alley of 'Dancing With the Stars' today.

According to Alley, she's made numerous attempts over the past year to have Groban follow her on Twitter, but he has yet to do so. "Over the last year, I've said, 'Josh. Oh, follow me Josh. Josh, follow me! Josh! Look at me!!'" she screamed. "I would like you to follow me. I'm pretty funny."

On 'Live With Regis and Kelly' (weekdays, syndicated), musician Josh Groban, who's filling in for Regis Philbin, finds himself seated between Heather Locklear and Kelly Ripa, and imagines that he's in a "babe sandwich."

"I'm the meat in a babe sandwich right now, is what I am," said Groban. "I'm blushing right now."

Since appearing on 'America's Got Talent,' 10-year-old opera prodigy Jackie Evancho has become famous. She'll be singing at Carnegie Hall -- making her the youngest solo female singer to perform there. Jackie also has her first major-label CD coming out, and it's already number one on Amazon.com.

On 'Oprah' (weekdays, syndicated), Oprah Winfrey asked Jackie how she's dealing with all this fame. Evancho is only in 5th grade, but she seems grounded. But she also has big dreams -- including a collaboration with an artist who wears a "meat dress."

'Glee' creator Ryan Murphy won't pipe down, but will he listen?

A new leak happens nearly every week about 'Glee' guest stars. John Stamos! 'Rocky Horror' originals Barry Bostwick and Meat Loaf! And Britney Spears (pictured at right, with Murphy and 'Glee's goddess of deadpan, Heather Morris).

So, Mr. Murphy, we herewith modestly propose a few out-there guest stars for your consideration, all sure to keep tongues wagging and the show humming.

This is Spoilers Anonymous, a weekly column here at TV Squad where we supply you with the dirt on some of the more popular shows on the air. We'll never put spoilers up here on the main page in order to help the reformed stay unspoiled. If you have anything to add to the group, feel free to step up and let yourself be heard, either with our tips form or by emailing us at tvsquad at gmail dot com, or call and leave a message at (775) 640-8479. Your anonymity is guaranteed, if you wish to remain as such.

This week we have spoilers for: 'Bones,' 'Brothers & Sisters,' 'Castle,' 'Chuck,' 'Desperate Housewives,' 'Eureka,' 'Fringe,' 'Glee,' 'Grey's Anatomy,' 'NCIS,' 'Private Practice,' 'Psych,' 'Smallville,' 'Supernatural,' and 'The Big Bang Theory.'

Sometimes Oscar bits work, and sometimes, they end up like the one on 'The Ellen DeGeneres Show' (weekdays, syndicated), in which Josh Groban and Ellen DeGeneres sang an ode to the Best Picture nominees.

Good effort, guys, and we appreciate the attention to detail, like dressing Groban up like a Na'vi from 'Avatar' and having him croon to characters from the Best Picture noms.

Still, you'd better keep your day jobs. Years from now, you'll look back on this as one of those "what was I thinking?" moments.

Watch the video after the jump.

The original 'We Are the World' was recorded almost exactly 25 years ago to benefit the charity, USA for Africa. Recently, 80 stars got together, including co-writer Lionel Richie and producer Quincy Jones, to remake the classic song to help with Haiti relief efforts. The video was supposed to debut last night during the Olympic opening ceremonies, but they just showed an excerpt. We have the full video here.

It's nice to see some of the same people involved in making the first video in the remake, but this version is populated by mostly new faces including Jennifer Hudson, Josh Groban, Wyclef Jean, and Kanye West, among many others. In fact, there were so many artists featured in this video, that I didn't even recognize them all. The new version is about a full minute longer than the original, and the real question is, how does it stack up?

One of the highlights of this year's primetime Emmys is going to be musical. That's right, I'm psychic. I've looked into the future and can tell you without equivocation that Josh Groban singing a medley of TV themes from 60 years of programs will stop the show.

On September 21, the night ABC broadcasts the big anniversary of the Primetime Emmys, producer Ken Ehrlich has tapped balladeer Groban for a four-minute medley of TV themes. The mind reels with the possibilities of how many memorable melodies he can fit into 240 seconds.

Some choices seem obvious: Cheers (where everybody knows your name), The Jeffersons (movin' on up to the big time), The Beverly Hillbillies (black gold, Texas T), The Flintstones (they're a modern stone-aged family).

Like I said, the possibilities are vast, and the promise of a something hilarious is sure fire.

Every year around this time, Oprah surprises her audience by announcing that they've come to the show on the day of her "Favorite Things" episode. The audience goes...well, berserk. You really can't understand what it's like if you haven't seen it. Imagine The Beatles, circa 1964. Then multiply by 6.

Yesterday she went to Macon, GA, the city that has given her show the best ratings over the years. To show her thanks, she gave her audience thousands of dollars worth of electronics, clothing, and food. I really hope she had medics on hand, because the audience when just as crazy for body lotion as it did for an LG fridge with a built-in HDTV. After the jump is the full list of stuff the Macon audience got and you didn't (and check out the video highlights).