The Premier League pair are two of a host of clubs monitoring the 19-year-old ace, who has been earning rave reviews for his performances in La Liga.
The winger has already been dubbed the ‘new Cristiano Ronaldo’ thanks to his direct playing style, skill and eye for goal, and is being tipped to be one of European football’s top stars in the coming years.
Spurs were rumoured to be watching the teenage sensation over the summer as they lined up possible replacements for Gareth Bale, but were deterred by Betis’ reluctance to sell.
However, with the Seville-based side struggling this term, they may alter their stance.
Vadillo is said to have a £17m release clause in his contract, but Betis might opt to accept an attractive offer below such a figure.
Liverpool are also keen, with Brendan Rodgers desperate to add a quality wide-man to his squad.
Manchester United and Arsenal are two other names to have been motioned as potential suitors.