My Bed hit the headlines when it was shortlisted for the Turner Prize - and displayed at Tate Britain - in 1999.
Earlier this month the notorious work fetched £2.54m at auction, a record for the artist, when it was bought by dealer and White Cube gallery owner Jay Jopling.
It has now emerged Jopling acquired the work on behalf of German industrialist and collector Count Christian Duerckheim, who has announced the long-term loan to the Tate for at least 10 years.
It is not yet known whether the bed will go on display at Tate Britain or Tate Modern and a gallery spokesman said details would be announced in the autumn.
Now 51 and a CBE, Emin made the piece, complete with stained sheets and discarded underwear, in her Waterloo council flat in 1998.
The work captured her chaotic life after a bout of suicidal depression following a relationship breakdown.
Millionaire collector Charles Saatchi, who bought My Bed for £150,000 in 2000, sold it at Christie's. He once displayed ut in the dining room of his Belgravia home.