Mueller signed on to co-star with Hilton's daughter Paris in new reality TV show The World According to Paris, but she had to quit the programme partway through and check into rehab.
But, in the latest episode of the show, which aired in the U.S. this week (begs06Jun11), Mueller is shown doubting her need for her sober companion, named only as L.W., citing the $400 (£250)-a-day cost as part of her decision to let him go.
Mueller also explains how she feels uncomfortable having L.W. sleeping on the floor of her bedroom at her Los Angeles home and "lurking around" to ensure she stays away from drink and drugs.
She says, "First of all I don't know if I need anybody anymore, and also it gets expensive, $400 a day. I think it's like $12,000 (a month)... He's just lurking around all the time...
"I don't think that L.W. serves a purpose anymore. I don't think I need him anymore... I think he's kind of creepy, he's always following me around... Am I gonna have a sober companion for the rest of my life? I can't afford it!"
Soon after parting ways with L.W., Mueller is shown struggling to keep her addictions under control and turns to Kathy in a desperate bid for help, weeping as she admits, "I feel like something really bad's gonna happen... I'm having really bad cravings, really bad urges... I just feel like I'm going to do something stupid. I think I have to go back to rehab... I just feel that I'm not strong enough, that I can't do this on my own."
Mueller, whose problems began when she was a teenager, completed her latest treatment stint last month (May11) and Kathy recently insisted her troubled friend is doing "very well".
The former Two and a Half Men star was running late for his one-man stand up gig on 19 April (11) after he was held up in a Los Angeles courtroom following a custody hearing with his estranged wife Brooke Mueller.
The actor faced a mad dash across the U.S. to make it to his concert on the east coast in time and revealed via Twitter.com he had been given special treatment by cops upon landing at Dulles International Airport in D.C..
Sheen, who eventually took to the stage an hour late, wrote, "In car with police escort in front and rear! Driving like someone's about to deliver a baby!"
He also posted a picture taken from the window of the car showing the police lights up ahead.
The blog posts landed Captain Robert Atcheson and Lieutenant Stuart Emerman in trouble with Special Operations Division bosses and an investigation was launched into the incident.
Now the Associated Press reports the two cops have been transferred to less high-profile positions to deal with patrol services and school security bureaus, although specific reasons for the move have not been given.
Mueller signed on to co-star with Hilton's daughter Paris in new reality TV show The World According to Paris, but had to quit to check into rehab for help with her ongoing alcohol and drug problems.
Sheen's ex has now checked out of treatment and the Hilton matriarch insists she's doing "very well" but her friend really is in trouble.
She tells U.S. news show Access Hollywood Live, "This is a serious disease, alcohol and drug addiction... It's a disease like cancer.
"I know Brooke from Palm Beach, from years ago... I know her mother and father and I adore them. We formed this bond and when this whole thing happened... She has had addiction problems since she was 17... and when the whole thing went down in Aspen (I realised she had a problem)."
Sheen was arrested on Christmas Day, 2009 after reportedly attacking Mueller in a fight at their winter retreat.
Hilton admits she had her reservations about Mueller going public with her problems on the reality TV show: "I said, 'Are you sure that you would wanna do this - because this show is an open book...' And she said, 'I wanna share my journey... Maybe I can help somebody through this.'"
Wednesday night's (08Jun11) episode of the reality show, which will air in America, features footage of an embarrassed Mueller coming to Kathy Hilton for help and weeping in front of her.
The hotel heiress, who has previously starred in small screen shows such as The Simple Life and Paris Hilton's My New BFF, has returned to TV in a new fly-on-the-wall series called The World According to Paris.
Hilton latest venture premiered in the U.S. on Wednesday night (01Jun11), and the first show got off to a saucy start as the socialite was seen stripping off for a bubble bath.
The 30 year old was shown soaking in the tub, covering her breasts with one arm, and lathering up and washing her hair.
The programme also showed Hilton arguing with her boyfriend Cy Waits after he found texts from a former lover on her cell phone, and featured a cameo appearance from Charlie Sheen's former partner Brooke Mueller, who is seen partying with the heiress at a nightclub.
Mueller reportedly entered a Los Angeles treatment centre earlier this year (11) to battle her longtime struggle with sobriety.
After undergoing help and recently walking free, Mueller received well wishes from pal Kathy Hilton after she missed the premiere of her daughter Paris Hilton's reality TV show, The World According to Paris, allegedly because the event was hosted in a nightclub setting.
In a post on her Twitter.com account on Tuesday (31May11), Kathy Hilton wrote, "Brooke, we r sorry u could not be with us tonight , we know your working on a bigger celebration your sobriety, we r very proud of u. XO (sic)."
Earlier that day, Mueller was snapped by X17 Online reuniting with her twins Bob and Max, who were temporarily staying at her parents' home while she completed her treatment and the boys' father, Sheen, was touring North America with his one-man comedy show.
Mueller won custody of the couple's sons before she reportedly checked into rehab.
Mueller's personal life has been in and out of headlines since Christmas 2009, when a heated dispute with Sheen left the actor facing domestic abuse allegations.
They are currently in the midst of divorce proceedings, but relations turned nasty again earlier this year (11) as Sheen embarked on a media blitz following his firing from hit TV comedy Two and a Half Men.
Mueller was filming appearances for Hilton's new reality show The World According to Paris as the drama unfolded, and the hotel heiress admits it was difficult to watch her pal suffer so publicly.
Speaking on The Tonight Show with Jay Leno on Friday (27May11), Hilton said, "You know, it was a lot of things going on during that whole Charlie thing during the show and I think she was going through a lot."
Mueller has since turned to professionals to help her overcome substance abuse problems, which Hilton claims began when her pal was in her teens.
Hilton continues, "Right now she's in treatment and I'm wishing her the best. She's going through a lot.
"It has (been hard to see). It's definitely been something that she has been struggling with since her teen years and it's a daily struggle."
The former Two and a Half Men star, who previously shared the pad with estranged wife Brooke Mueller, has placed the house up for sale in a bid to move on from his hard partying ways and damaged reputation.
The Beverly Hills estate, which Sheen dubbed Sober Valley Ranch, is listed for $7.2 million (£4.5 million) and boasts five bedrooms, a landscaped yard, an outdoor pool and spa, as well as a top-of-the-line screening room, reports TMZ.com.
Charlie, who has battled substance abuse issues, was fired from hit sitcom Two And A Half Men earlier this year (11) as a result of a public feud with TV bosses.
It came amid several headline-grabbing incidents, including rehab and hospitalisations, following his split from wife Brooke Mueller after their heated altercation on Christmas Day (25Dec) 2009, which left the actor with an assault conviction.
His father Martin has previously likened his son's addiction problems to a cancer, but he is now feeling more upbeat about Charlie, who has just wrapped his My Violent Torpedo Of Truth/Death Is Not An Option tour of the U.S. and Canada.
He tells Britain's OK! TV, "He's doing very well, thank God. At the mention of his name, in any circumstances, (I ask) for people to pray for him, lift him up, because he's got a real chance. That's the best thing we can do for him right now, to lift him up, to pray for him."
The former Two and a Half Men star, who divorced Richards in 2006, met with the former Bond girl at a Los Angeles law office on Tuesday (10May11) to negotiate his desire for weekend visiting rights with daughters Sam, seven, and Lola, five, reports TMZ.com.
However, Richards allegedly rejected his plea because of her concerns about her children's welfare.
Sheen, who has become a tabloid regular in recent months thanks to his bizarre behaviour, recently lost his bid for full custody of the twin boys he shares with estranged wife Brooke Mueller.
The matter is not expected to be taken to court.
"I am teaching them (twin sons) words, because they're speaking now. I'm teaching them the word 'rehab' so they always know where their mum is." Troubled actor Charlie Sheen pokes fun at his ex-wife Brooke Mueller following her previous stints at a treatment facility.
Met April 2006; Announced engagement July 2007; Married May 30, 2008; Sheen filed for divorce Nov. 1, 2010, stating in documents that they separated the same day as a Christmas 2009 altercation that led to assault charges against him; Divorce finalized May 2, 2011