The British have become far more comfortable than they used to be with interracial marriage, according to a report.
Research by British Future estimates that more than a million people in Britain are now of mixed parentage.
It came as census data from the Office for National Statistics (ONS) showed a significant increase in the number of mixed race people living in the UK.
The think-tank's report, The Melting Pot Generation - How Britain Became More Relaxed About Race , says "mixed Britain is fast becoming the new normal" .
It points to famous mixed race people such as Jessica Ennis, Lewis Hamilton and Leona Lewis as being key influences on public acceptance.
Olympic heroine Ennis was born in Sheffield in 1986 to a Jamaican father and English mother.
At that time, a British Social Attitudes survey showed 50% of the public were against marriage across ethnic lines. The figure dropped to 40% in the 1990s and now stands at 15%.
Official census data also showed that the number of foreign-born residents living in England and Wales increased from 4.6 million in 2001 to 7.5 million in 2011 - 13% of the population.
The number of Christians living in England and Wales last year was four million lower than in 2001 - their numbers fell from 37.3 million to 33.2 million, the ONS revealed.
Sunder Katwala, director of British Future, said under-30s were Britain's most tolerant generation.
"One in four of the over-65s still say that they would be uncomfortable about a child or grandchild marrying somebody from a different race, but that falls to one in 20 of those under 25.
"It ranked last out of 10 as a possible source of concern, with even worries about the idea of marrying somebody much richer being slightly stronger among the youngest group."
He said the "Jessica Ennis generation" are much more likely to be mixed race, with one in 10 children growing up with parents from different backgrounds.
"Over a million Britons will have ticked the census box as mixed race - and that is only half the story of the rapid growth of mixed Britain," he said.
"Twice as many people have ethnically mixed parentage - but over half of them choose other census categories, such as black or white."
The think-tank believes that Britain has a greater claim to "melting pot" status than the US.
It points out that in America most mixed race people marry someone from an ethnic minority - as with Barack and Michelle Obama - whereas three quarters of Britons with mixed parentage marry white people.