The Jataka, Vol. II, tr. by W.H.D. Rouse, , at sacred-texts.com
"Your own idea," etc.--This story the Master told while staying at Jetavana, about a young lady.
She was the only daughter of a rich merchant of Sāvatthi. She noticed that in her father's house a great fuss was made over a fine bull, and asked her nurse what it meant. "Who is this, nurse, that is honoured so?" The nurse replied that it was a right royal bull.
Another day she was looking from an upper storey down the street, when lo, she spied a hunchback.  Thought she, "In the cow tribe, the leader has a hump. I suppose it's the same with men. That must be a right, royal man, and I must go and be his humble follower." So she sent her maid to say that the merchant's daughter wished to join herself to him, and he was to wait for her in a certain spot. She collected her treasures together, and disguising herself; left the mansion and went off with the hunchback.
By and bye all this became known in the town and among the Brotherhood. In the Hall of Truth, brothers discussed its bearings: "Friend, there is a merchant's daughter who has eloped with a hunchback!" The Master came in, and asked what they were all talking about together. They told him. He replied, "This is not the first time, Brethren, that she has fallen in love with a hunchback. She did the same before." And he told them an old-world tale.
Once on a time, while Brahmadatta was king of Benares, the Bodhisatta was born of a rich man's family in a certain market town. When he came of age, he lived as a householder, and was blessed with sons and daughters, and for his son's wife he chose the daughter of a rich citizen of Benares, and fixed the day.
Now the girl saw in her home honour and reverence offered to a bull. She asked of her nurse, "What is that?"--"A right royal bull," said she. And afterward the girl saw a hunchback going through the street. "That must be a right royal man!" thought she; and taking with her the best of her belongings in a bundle, she went off with him.
The Bodhisatta also, having a mind to fetch the girl home, set out for Benares with a great company; and he travelled by the same road.
The pair went along the road all night long. All night long the hunch-back was overcome with thirst; and at the sunrise, he was attacked by colic, and great pain came upon him. So he went off the road, dizzy with pain, and fell down, like a broken lute-stick, huddled together; the girl too sat down at his feet. The Bodhisatta observed her sitting at the hunch-back's feet, and recognised her. Approaching, he talked with her, repeating the first stanza: 
And hearing his voice, the girl answered by the second stanza:--
And when the Bodhisatta perceived that she had only followed him in disguise, he caused her to bathe, and adorned her, and took her into his carriage and went to his home.
When this discourse was ended, the Master identified the Birth:--"The girl is the same in both cases; and the merchant of Benares was I myself."