The 28-year-old was a key performer in Jose Mourinho's title-winning Chelsea team of two years ago, making 35 league appearances as the Blues were crowned champions.
And the now-United manager appears to have made attempts to take the winger to Old Trafford, with Willian explaining that enquiries were made in the summer.
He told Globo Esporte: "There were enquiries, yes. It was from Manchester United, because Mourinho is there too.
"From other clubs I don't know but there are always some things on the internet. I'm glad to hear that there are clubs that admire my work."
Willian's former Chelsea team-mate Ramires made the move to China in the summer, but the Blues star is unsure if he'd follow in his compatriot's footsteps.
He added: "I do not know if I would go or not. What I can say is that I'm happy at Chelsea, I feel very good there, like it's my home.
And despite not starting as many games as the likes of Eden Hazard and Diego Costa, Willian appears to be a fan of Antonio Conte.
He continued: "We [the team] had a difficult start, but then we got it right. He is coaching, coaching, helping all players.
"It is worth mentioning the group of players also, who managed to understand his philosophy of work, take ideas into the field and do a good job."