The Brazil international's current deal at Stamford Bridge is due to expire at the end of June, but he has already allegedly agreed a contract with Spurs ahead of the 2020-21 campaign.
Arsenal, Barcelona and Liverpool have both recently been credited with an interest in the 31-year-old, but Jose Mourinho's presence at the Tottenham Hotspur Stadium appears to have helped Spurs jump to the head of the queue.
Willian has been a key player for Frank Lampard's side this term, scoring seven times and contributing six assists in 37 appearances, but the attacker has thus far been unable to agree a new deal with his current team.
Here, Sports Mole looks at how Tottenham could line up if they bring Willian to the club ahead of the 2020-21 campaign.
The coronavirus outbreak is likely to have a significant impact on Tottenham's summer spending, meaning that it would not be a surprise to see limited business for the club ahead of the 2020-21 campaign.
Tanguy Ndombele will reportedly stay at the club despite suggestions of interest from Barcelona, and the France international is said to be determined to prove himself after a difficult first year in English football.
Giovani Lo Celso was arguably the club's most in-form player before football was called to a halt and is likely to be in Mourinho's plans for a starting XI, while Son Heung-min is a certainty on the left.
Harry Kane is also likely to stay despite the recent speculation surrounding his future, while Hugo Lloris should keep his spot between the sticks despite some inconsistent form over the last 12 months or so.
Jan Vertonghen is expected to leave on a free transfer, but Toby Alderweireld has signed a new deal and could line up alongside Davinson Sanchez, with Serge Aurier and Ben Davies in the two full-back positions.
Dele Alli, meanwhile, has scored eight times in 22 Premier League appearances this term despite his troubles and will surely be keen to make a point next season after being the subject of criticism in recent months.
A 4-2-3-1 formation leaves one final position open on the right, and Willian could fill that spot for Mourinho's side. Despite Lampard favouring youth this season, the South American has still been a key player for the Blues, contributing seven goals and six assists in all competitions.
He has played off the right in 23 of his 37 appearances at club level this term, scoring four times and providing six assists when starting in that area of the field.
Willian netted twice against Spurs at the Tottenham Hotspur Stadium earlier this season, meanwhile, and would certainly provide Mourinho's side with some extra quality in the final third.