This is true.
It was narrated from Ibn ‘Abbaas (may Allah be pleased with him) that the Messenger of Allah (blessings and peace of Allah be upon him) said to a woman of the Ansaar: “What kept you from performing Hajj with us?” She said: We only have two camels and the father of her son and her son had gone for Hajj on one camel, and he left us the other camel so that we could carry water on it. He said: “When Ramadaan comes, go for ‘Umrah, for ‘Umrah in (that month) is equivalent to Hajj.”
Narrated by al-Bukhaari (1782) and Muslim (1256)