This is Reading's first signing of the summer, after having an embargo put on them for breaching the EFL's Profit and Sustainability rules.
Dele-Bashiru joins after recovering from an anterior cruciate ligament injury, which he incidentally suffered in Watford's 1-0 loss to Reading last October.
Dele-Bashiru first started out at Manchester City, where he came through their academy, featuring for their youth teams alongside the likes of Jadon Sancho and Phil Foden.
After progressing through the Academy, he got his first taste of professional football, when he came on as a substitute for City in their Carabao Cup Quarter-final against Leicester City in December 2017. He helped them get to the semi-finals that evening, where they would then go on to win the competition.
A year-and-a-half later and he was released by Manchester City, after failing to break into the first team on a regular basis. He then joined Watford, signing a six-year-deal, running until 2025.
He made his debut for the Hornets coming off the bench against Coventry City in August 2019, as they progressed to the third round.
He then made his full debut in the FA Cup Third Round, and he also scored as Watford came from three goals down to draw with 3-3 with Tranmere Rovers.
He made his first Championship appearance last season, coming on against Luton Town, replacing former Royals loanee Nathaniel Chalobah. He then started his first Championship game against Reading, but unfortunately suffered an anterior cruciate ligament injury during the game, forcing him to miss the rest of Watford's promotion-winning campaign.
How will he fit in at the Select Car Leasing Stadium?
Primarily a centre-midfielder, he will probably struggle to get a starting spot in the team at first. Reading manager Veljko Paunovic prefers to play a 4-2-3-1, in which his central midfielders are a double pivot in front of the defence in Andy Rinomhota and Josh Laurent, and a centre attacking midfielder in John Swift.
All three are experienced players in this division and have been pivotal to the way Paunovic plays. He will likely start on the bench, but if he keeps up some good performances, he may start some games soon. But with Reading's current depth, he will almost definitely come off the bench and feature.