Why does telemachus think that odysseus is a god? how does odysseus explain his sudden transformation?

Telemachus believes Odysseus to be a god because initially, Odysseus is disguised as a beggar so as not to be recognized when facing the suitors. However, right in front of Telemachus's eyes, he transforms into a young, healthy looking person. Odysseus, however, has transformed thanks to the help of the goddess Athena. She is the one who suggested Odysseus to be disguised, and she is also the one who helped him achieve such as remarkable disguise.