The teen yobs pelted the X Factor champ's car and shouted threatening abuse.
So Alexandra, 21, whose hit Hallelujah was last year's biggest-selling single, begged record company bosses to move her from the plush two-bedroom London apartment.
They agreed and now the star, is holed up into the former home of standout Fame Academy singer LEMAR in a suburb of the city while she gets ready to launch her own attack - on the pop charts.
A worried pal said: "It all happened when she got back from recording her album in LA.
"This gang wouldn't leave her alone and it took a real toll on her.
"One day Alex was driving her Mini Cooper convertible with the roof down to her flat when these lads just started throwing stones and hurling abuse at her and a friend.

"They were shouting: 'Oh you think you're so f***ing amazing because you went on the f***ing X Factor'.
"One of the rocks hit her friend. Alex was horrified and realised she had to get out of there."
The source added: "She didn't care where she lived or what kind of place she had.
"She just wants to be safe, secure and left in peace. She's much happier now."
From the looks of my eXSclusive photo of her recording the video for new single Bad Boys (how appropriate!) she's back on top form.
Alex told me yesterday: "In the studio, after I'd done the first verse, I stopped singing and said to the producers, 'Do you realise how much I can relate to this song?'
"This is what I do. I go for the bad boys! I go for the boys I'm not meant to. I just knew that it had to be the first single.
"I texted SIMON COWELL saying 'Bad Boys for first single?'
"He texted straight back saying 'most definitely'."
And after this horror attack, I'm glad you have finally escaped one set of Bad Boys for good, Alexandra.

ALEX will fight a returning Bad Boy in the biggest No1 battle of 2009. Her first single off the new album is out October 12 - the same day as ROBBIE WILLIAMS' comeback Bodies.
I'm backing Alex, an exciting new talent.
The next week will also see a proper tussle with CHERYL COLE, top left, releasing her excellent first solo single, Fight For This Love, up against the War Child charity single.
Please note: All comments are moderated.
Tick this box to accept our
TERMS & CONDITIONS
This article has 31 comments
hi alexandra my little girl charlotte is your biggest fan she allways dreams about what your doing where you live and she allways dreams of being your sister. I wonder what you do when you are board.
By dominique white.. Posted November 27 2009 at 5:25 PM.
alistar really needs to get a life, don't compare her to Leona when LEONA CAN ONLY DO BALLADS, ALEX IS More VERSATILE, SHE CAN SING, DANCE AND DO UPBEAT!
By mimi.. Posted October 15 2009 at 10:39 PM.
Alex deserved to win and is an amazing talent, she is a brilliant singer and dancer and is very humble.
By Gem.. Posted October 12 2009 at 8:05 PM.
i am loving this song and will show some love to Alex, because she is a good singer.
By hayi.. Posted October 11 2009 at 10:04 AM.
luv u alex! you are such a good singer, but personally i think jls should have won, no offence.
i'm a joe jonas fan aswell, luv u sooo much joe, i'm your future wife (of course) soz there girls, he's mine! luv ya xxx
p.s i'm a future pop star aswell! :)
By etienne.. Posted October 5 2009 at 6:07 PM.
IYA U GABRIELLA I WAS A JLS FAN TOO SHE CAN SING SO GET URE FACTS RIGHT SH WON SHE WAS GOOD END OF STORY SO KEEP THAT MOUTH SHUT SOZ
By ALISHA COLE .. Posted September 18 2009 at 7:19 AM.
So glad you're safe now Alex JLS fans just wait till Anext year when Alex is a wordlwide star you guys are just jealous cos Alex won and they did
By Sarah.. Posted September 14 2009 at 11:52 PM.
Did she cry when she rang Simon? That's all she ever seemed to do on the show. A good singer but certainly no Leona Lewis. But good or bad she doesn't deserve that sort of rubbish from yobs
By Alistair .. Posted September 14 2009 at 11:45 AM.
I can't believe how immature JLS fans are. Even on their forum they don't give it a rest about how Alex is "crap"
They're being pathetic, immature and disgusting people. Alex won, get over it! They know full well that Alex can sing, does have talent, and is probably going to go global really soon, but they do their best to act like little girls and put her down.
Get over it guys, shes amazingly talented and she won. Accept that.
By Jordan.. Posted September 14 2009 at 9:00 AM.
Not the worst voice in the world, but nothing special, definitely not much to look at, and the latest single is AWFUL! Such a monotonous melody and she doesn't even do much singing on it, more like talking.
By M.Salanki.. Posted September 14 2009 at 3:03 AM.
Alex is hugely talented and deserved to win. She has a huge career ahead of her, loving 'Bad Boys', definitely a number 1.
By Brian.. Posted September 14 2009 at 1:29 AM.
So what if she didnt write the song herself - she is a singer - there are some bitter and twisted people out there !!!
JLS do have alot of immature, jeaous little fans out there - they still cant accept the fact she won :/
Alexandra has talent - you go girl X
By nikki.. Posted September 14 2009 at 12:29 AM.
Not surprised she is annoying.
By BR.. Posted September 13 2009 at 7:11 PM.
JLS fans have no class and cannot accept the group lost to a better singer and performenr maybe becuse they are so young and immature they think they will end up JLS wives. Alex is great with a big career ahead of her unlike JLS she works hard and is commited to doing her best-Bad Boys wil be No 1 get used to it.
By Bernard.. Posted September 13 2009 at 6:44 PM.
God she's annoying ! very up herself and boring...she thinks she's already made it, but in truth the singers of old had to slog there guts out for years to get to where she is...the new single sounds like something Sinnitta would have sung 20 years ago !!!
By I want outttt !.. Posted September 13 2009 at 4:47 PM.
give it a rest!! 'jls are better', if they are they would of won? and its over now so get over it... wishes alex all the best, hes song is wicked, even though everyones saying its rubbish, but there again everyone on here always got nothing but negative things to say :/
By Jamie B.. Posted September 13 2009 at 3:17 PM.
I love Alexandra, she doesn't deserve all this hate, she performs her heart out and loves her fans. If you don't like her and prefer JLS, don't bother commenting on things that concern Alexandra. 'Bad Boys' is an excellent song and to be honest, i'm glad it's not a ballad and that she's actually taken a risk, instead of sticking with the usual xfactor formula. Cmon Alexandra, that number one spot is waiting for you!
By matthewtings.. Posted September 13 2009 at 3:15 PM.
I'm no fan of Alexandra, believe me, but to do that to someone is a horrible, nasty and discusting thing to do. What did she ever do wrong other than having talent??
By A M.. Posted September 13 2009 at 2:34 PM.
Ermmmm... Who Won By OVER A MILLLION VOTES??? Oh Yeah... Alex!!
JLS LOST BY OVER A MILLION!! Hahahaaaaa Which Means They HAD NO CHANCE!! Get Over It!!
Her Single WILL Hit Number One!! Its Gonna Be HUGE!! Stopping Be So Bitter!!
By SuperGirl.. Posted September 13 2009 at 2:07 PM.
For goodness sake; Alex went in for a competition and won by a mile so get over it all you green eyed monsters. Good luck Alex.
By jen.. Posted September 13 2009 at 12:15 PM.
Poor girl so many jealous people around, You hold your chin up and strut your stuff, i backed you all the way on X factor and glad you won. you give it what you got hun and forget the losers, you can sing and don't you forget it .
By mandy .. Posted September 13 2009 at 12:14 PM.
Why are there so much haters for Alex. Give her some love you pack of miserable **** The girl have done good regardless.
If you have a talent go and use it!
By marie.. Posted September 13 2009 at 12:09 PM.
give her a year or two, she will be forgotten about like all the other x factor stars apart from leona lewis obviously :)
By kerry.. Posted September 13 2009 at 10:47 AM.
her surmane says it all. burke!!! she nothing to look at either. jls jls
By lisa.. Posted September 13 2009 at 10:21 AM.
so i ugly mug, grates on you and thinks she gods gift. get a life alex. you cant sing. jls miles better.in few year alex??what a burke
By sue.. Posted September 13 2009 at 10:20 AM.
Here today and gone tomorrow,
another pop star misfit nearing the end of their 5 minutes of fame,
In a years time I here you asking,
What was her name?
By ben.. Posted September 13 2009 at 9:09 AM.
what a dissapointment this song is, nothing special about it at all...it's quite mundane
By ant.. Posted September 13 2009 at 9:08 AM.
Its a right let down, the single sounds so dated.
By Jay.. Posted September 13 2009 at 8:46 AM.
I still don't know why she won. JLS were far better. I think singing with Beyonce was what did it for her.
I'm not saying she can't sing. I just found her to be quite annoying.
By Gabrielle.. Posted September 13 2009 at 7:25 AM.
So didn't write the song yourself then, what a suprise.
By R Collins.. Posted September 13 2009 at 1:57 AM.
It is a shame that there are so many bitter hateful people around-chin up Alex your single Bad Boys will be huge and I am sure you will have another No 1. Although you would have to be deaf to think that Cheryl Cole's new song is excellent it is utter rubbish.It also seems strange that she is releasing it so soon after Alex.
By Ben Marr.. Posted September 12 2009 at 11:36 PM.