Just how replaceable ARE "American Idol" judges?  According to "Idol" champ Taylor Hicks ... SUPER DUPER REPLACEABLE.

Taylor was out in L.A. on Friday when our photog asked the season five winner the only interesting thing left to ask about "Idol" ... is it time to replace ALL the judges?

Randy Jackson -- the last remaining original judge -- made his exit after the season finale, and it's been reported that newbie judges Nicki Minaj, Mariah Carey and Keith Urban are all on the chopping block.

But Taylor is unfazed by the "A.I" shake up and believes the "revolving door" of judges COULD be a way to save the slowly dying show.

And in case you forgot who Taylor is, here you go:

The Dawg is putting his "American Idol" career to sleep -- Randy Jackson just announced he's leaving the show for good at the end of the season.

Jackson -- who's been with the show from the very beginning -- just released a statement saying, "Yo! Yo! Yo! To put all of the speculation to rest, after 12 years of judging on 'American Idol' I have decided it is time to leave after this season."

Randy continued, "I am very proud of how we forever changed television and the music industry. It's been a life changing opportunity but I am looking forward to focusing on my company Dream Merchant 21 and other business ventures."

Story developing ...

In case you forgot ... Nicki Minaj STILL HATES Mariah Carey ... and moments ago, she went after the diva AGAIN ... calling her a bitter old woman with no personality.

Minaj just unloaded on Twitter, following a series of heated exchanges on "American Idol" last night.  During the show, Mariah spit a little trash talk Nicki's way ... and taunted her for never having a #1 single on the Billboard Hot 100.


Nicki took some shots back at Mariah on the show -- at one point breaking out a cotton swab and telling Mariah to clean out her ears.

But moments ago, Nicki continued the war on Twitter ... telling critics to ask themselves "Why a woman SO successful at her age, is still so INSECURE, and bitter."

Minaj also made a reference to reports that "Idol" producers were recently looking to replace Mariah with former judge Jennifer Lopez:

"All dem #1s but JLo phone ringin? Lol. I guess having a personality, being a secure woman, and giving genuine critique still trumps that." So far, no response from Mariah.

Of course, Nicki and Mariah have been at each other's throats since before the season even began ... 'memba this video from last year?

Right before Jason Aldean filed for divorce ... the country star called the "American Idol" hottie he kissed behind his wife's back and warned her about the media firestorm to come ... TMZ has learned.

Sources connected to Brittany Kerr tell us ... Aldean placed the courtesy phone call himself last week ... and politely warned the singer that he was pulling the trigger on his marriage to his high school sweetheart Jessica Ussery.

Translation -- the media's gonna be all over your ass again ... so, govern yourself accordingly.

We're told Kerr appreciated the heads-up ... considering she was Aldean's kissing partner on the night he cheated on his wife back in Sept.

Since the warning, Brittany's been laying low -- shutting down her social media pages and staying out of the public eye.

It's not clear whether Aldean and Kerr have communicated since … or whether their relationship has a future.

Country superstar Jason Aldean is pulling the trigger on his marriage ... filing for divorce from the woman he cheated on at a Hollywood bar just a few months ago. 

Aldean filed papers in Tennessee on April 26 -- moving to end his 11 year marriage to high school sweetheart Jessica Ussery ... the mother of his 2 children. In the docs, Aldean blames the split on "irreconcilable differences."

FYI -- the 36-year-old singer filed the divorce papers on the same day he announced he and his wife had separated. At the time, Aldean's rep had said the couple was "having problems," but made no mention of the divorce,

The problems began for Aldean when he was pictured kissing Season 11 "American Idol" contestant Brittany Kerr on the Sunset Strip in September while he was in L.A. for a concert.

Aldean and Ussery initially tried to patch things up -- and they even walked a red carpet side-by-side back in November ... but clearly, that didn't work out.

Jason Aldean and his wife have separated ... after the country superstar was pictured kissing another woman on the Sunset Strip back in September ... sources connected to the couple tell TMZ.

We're told Aldean and his high-school sweetheart Jessica Ussery have been struggling ever since the "Dirt Road Anthem" singer put the moves on Season 11 "A.I." contender Brittany Kerr in front of a bunch of people at a Hollywood bar.

Aldean and Ussery initially tried to move past the incident together -- and they even walked a red carpet side-by-side back in November.

But now, Aldean's rep says the couple is "having problems" ... and sources tell us they've decided to take some time apart.  The split was first reported by Us Weekly.

Aldean and Ussery have been married since 2001 and have 2 kids together.

Jennifer Lopez has been approached by Fox execs to return to "American Idol" for the balance of the season ... to replace Mariah Carey ... sources connected with the network confirm to TMZ.

We've learned Lopez will appear on the now ratings-challenged show on May 16 to debut her new single, but Fox has bigger ideas -- they want to stop the hemorrhaging quickly and bring the former judge back on the show.  The Hollywood Reporter first posted the story that JLo could be returning.

And the show is in trouble.  Last week's ratings were the worst since the show debuted in 2002.

Sources tell us Fox is scrambling to find a solution, and ironically they think Lopez could be the answer.  We say ironically because network execs would not ante up the cash JLo wanted to stay on the show this season. 

We're told as of now ... no deal has been made.

UPDATE:  A Fox spokesperson tells TMZ ... "This is just another ridiculous "Idol" judge rumor, likely started by talks of Jennifer performing on the finale."

Clay Aiken's alleged stalker really wanted to get a good look inside the singer's house ... because according to the 911 call, the woman was armed with binoculars when she hopped his fence.

TMZ broke the story ... 57-year-old Barbara Saylor was arrested outside Clay's North Carolina house April 3rd after allegedly hopping his fence and then peering inside his front window. Clay was home.

It wasn't apparent just how bizarre the incident was ... until now.  Check out the 911 tape.

Babs was eventually arrested for stalking and trespassing. She's due in court April 24.

Frightening moment for Clay Aiken ... when an obsessed fan broke on to his property and made it all the way to his front door ... this according to police docs obtained by TMZ.

According to the docs, it all went down on April 3 ... when the fan -- 57-year-old Barbara Saylor -- snuck into Clay's gated community in North Carolina and hopped a fence surrounding the singer's home. Sources connected to the incident tell us the woman was seen trying to peer into a window at the front of the house.

The scary part -- Clay was home at the time.

Someone called 911 -- and cops responded to the scene. Barbara was eventually arrested for misdemeanor stalking and misdemeanor first degree trespassing.

According to the docs, Clay told police it's not the first time the woman -- who lives in the Seattle area -- crashed Clay's N.C. pad. Aiken told cops Barbara had previously "thrown her phone over the fence and reported she had been invited by the victim when actually she had not been."

Sources close to Clay tell TMZ ... the singer was shaken up by the incident ... but he's grateful to local law enforcement for responding so quickly.

The woman is due in court on April 24.

Justin Bieber's recent wave of d-bag shenanigans has not gone unnoticed in the music world ... so when we asked "American Idol" honcho Nigel Lythgoe if the Biebs was "Idol" mentor material, his response was ... mixed.

Nigel was out in Malibu and our photog questioned whether Lythgoe would consider having JB on the show to help shape the minds of "AI" hopefuls. A valid question in light of Bieber's recent run of speeding tickets, fights, drugs, monkey smuggling ... you get it.

Nigel's response is pretty hilarious and he also addressed whether or not Nicki Minaj is welcome back on the show next season.

The two biggest reality shows on the planet are about to come together -- TMZ has learned the identity of four of the contestants for this season of "Dancing With the Stars" ... including the first ever former "American Idol" wannabe.

"DWTS" has not revealed their cast for the upcoming season yet ... but sources close to the show tell TMZ that Kellie Pickler -- everyone's favorite country bumpkin from season five of "Idol" -- will be doing this season of "DWTS."

In addition to Pickler, our sources say country star Wynonna Judd, "Bachelor" star Sean Lowe and 2012 Olympic gold medal winning gymnast Aly Raisman are among this year's cast.

Not that TMZ condones gambling, but put $20 down on Raisman -- three former Olympians have won the show in the past. You're welcome.

A rep for the show tells TMZ, "We do not comment on casting rumors, but tune in to 'GMA' on Tuesday when we reveal the cast live!"