That certainly is an element but whether that story is an urban legend or not is matter of much debate:
“Along with Iqbal Wahhab, now of Roast Restaurant, I started the urban myth of CTM being tikka with added Campbell’s tomato soup and spices for a joke,” admits Grove. “Yet somehow it has become accepted as the official explanation the world over.”
That certainly is an element but whether that story is an urban legend or not is matter of much debate:
“Along with Iqbal Wahhab, now of Roast Restaurant, I started the urban myth of CTM being tikka with added Campbell’s tomato soup and spices for a joke,” admits Grove. “Yet somehow it has become accepted as the official explanation the world over.”
https://roadsandkingdoms.com/2014/who-owns-chicken-tikka-masala/