Alice Arnold, broadcaster and partner of sports presenter Clare Balding, said Daley's coming out video would help his career.
She told Channel 5 News:
It will make him a better diver, because if you've got that monkey on your back you're worried all the time.
It takes a lot of energy to live a secret life and he doesn't have to live a secret life, and that will improve everything for him and for everyone around him.
Ms Arnold said Daley's move would help other gay athletes.
If you look on social media there is still some very bad attitudes amongst the very young in schools and I think he will help that.
I hope that his coming out will help that a lot.
He needs to talk about it because if he wants to go for a meal in a restaurant with his boyfriend there will be cameramen outside waiting for him, paparazzi waiting for him, hounding him every step that he takes.
Tom Daley said it was "love at first sight" when he met his partner, in his first interview since revealing he is in a gay relationship.
Olympic diver Tom Daley has revealed in an online video that he is in a relationship with a man.