The 23-time major champion said that winning is not her biggest priority when she takes the court at the Queen's Club Championships on Tuesday with doubles partner Victoria Mboko, a Canadian 25 years her junior, with the chance to compete again its own reward.
"I don't need to win. I've won more than most people have in their whole lives," Williams said on Sunday.
"It's important that I keep reminding myself of that because I don't have anything to prove. I don't have anything to lose. And everything here is just a gain."
Williams, who won the last of her 23 grand slam singles titles in 2017, told reporters in London that she had had a change of heart since shooting down earlier reports of a return.
"It was just talking to a few people and just chatting about different possibilities of just having fun. You know, something a little bit different," said Williams, who said she has not yet decided whether she will compete in singles.
"I just kept talking, and talking, and then, I was like, 'Well, why not?' for lack of a better explanation."
Her return to the court sees her unite with up-and-coming talent Mboko, who was born seven years after Williams picked up her first major singles title at the US Open and grew up idolizing the American tennis icon.
"She could probably take years off and when she steps on the court she could probably find that rhythm again and find her timing. So, I think that's really a God-given gift she has," said Mboko. "She's ready to go."
Williams and Mboko play on Tuesday in the opening round of the women's doubles against American Nicole Melichar-Martinez and New Zealand's Erin Routliffe, the third seeds.
