Artist Tracey Emin wiped away tears as she unveiled her £2.54 million unmade bed - complete with discarded condoms - on its return to its "home" at the Tate.
My Bed became notorious when it was shortlisted for the Turner Prize and displayed at Tate Britain in 1999.
Over 15 years later, it is back at the gallery on a long-term loan for at least 10 years.
Emin admitted that unlike the chaotic-looking installation, which features empty vodka bottles, cigarette butts, stained sheets and discarded underwear, her bed at home is now a different affair.
"I make my bed every day. It's so boring, it's very neat. I'm really OCD (obsessive compulsive disorder)," she said.
Wiping away tears, the artist said that seeing the work - which is now subject to rigorous security in the form of a sensor and a guard to prevent visitors from getting too close - left her emotional.
"I'm 52 nearly. Even though I was quite old when the bed came into fruition I didn't look old or behave old," she said.
"I'm a bit tearful, It means a lot to me. I feel pathetic but there are things on that bed that have no place in my life any more.
"That bed belonged to a young woman and hopefully in 20 or 30 years' time the bed will be here but I won't probably.
"That's what art's about. It's about a legacy, about making something which goes on without you.
"It's a statement of history and now it's in safe hands ... it will never change."
The work, which expressed the artist's suicidal depression following a relationship breakdown, is displayed in its own room alongside two paintings by Francis Bacon and six nude drawings by Emin which she has given to the Tate.
Emin said she felt validated seeing the installation on display alongside works by some of Britain's "greats" after all the criticism about the bed at the time.
"I love it, why wouldn't I? I was right ... It's a good feeling ... it feels like home," she said, later adding that her fellow students at art school had "thought I was a bit thick".
Earlier at a photocall, Emin told photographers: "I think I look like the cat who got the cream. I feel so happy."
She later added: "My Bed is a symbol of that time. It was a zeitgeist. It was perfect for that moment. It has captured a part of history."
Pointing to her belt on the installation, she added: "I would be lucky if it fitted around my thigh now and it used to fit around my waist.
"There are so many things about that bed that don't relate to my life any more.
"It's a time capsule of a woman living in the 1990s in a really wild way. It's not just sad, but how that bed came about was through sadness.
"It's also about being in the worst situation in your life and being able to pull through and get out to the other side."
Tate director Sir Nicholas Serota said: "It's a work we've always wanted to bring into the collection.
"It was quite clear from 1999 when it was first seen in the Turner prize that it was going to be regarded as one of those iconic works from the late 90s."
The "really important work" was being given "a historical dimension", he added as "part of the story of British art over a long period".
My Bed is on long-term loan to the Tate and will be shown at Turner Contemporary in Margate - Emin's home town - and Tate Liverpool.
The work fetched £2.54 million at auction, a record for the artist, when it was purchased by dealer and White Cube gallery owner Jay Jopling last year.
It later emerged that Jopling acquired the work on behalf of German industrialist and collector Count Christian Duerckheim, who announced the long-term loan to the Tate for at least 10 years.
Sir Nicholas said that he hoped that the Tate would be able to hold on to My Bed for longer than 10 years.
"I'm sure we could keep it. This is a collector who has been incredibly generous. It's all to play for," he said.
My Bed was one of the key works of the 1990s Young British Artists (YBA) movement.
Now 51 and a CBE, Emin made the piece in her Waterloo council flat in 1998.
Millionaire collector Charles Saatchi bought My Bed for £150,000 in 2000 and sold it at Christie's.
:: Tracey Emin's My Bed 1998 opens at Tate Britain tomorrow.