Okoye joined the Hornets tbis week from Dutch club Sparta Rotterdam penning a five-and-a-half-year contract that will come into effect on January 1, 2022.
The 22-year-old will then return to Sparta Rotterdam on loan until the end of the current campaign.
“I’m delighted to see Maduka sign for Watford,” the 28-year-old told the club’s official website.
“I’ve been speaking to him for a while about the different options he’s had, and I knew the club were speaking to him, so it’s great that it’s over the line.
“We’ve spoken about playing in England before, and I had mentioned Watford. He’s a very humble kid and he’s kept his cards close to his chest, but I did say if the chance came around he had to jump at it.
“He’s been part of the Nigeria team for the last two years or so now, and over that time he’s made some fantastic steps. He moved to Holland from Germany and it’s been incredible to see him take on the responsibility that comes with being a No.1.
“He’s a very reliable goalkeeper with a huge will to learn, and I think he’ll add a lot of strengths to the squad when he links up with us next year.”
Okoye has been capped 13 times by Nigeria and won Sparta Rotterdam’s Player of the Season award last term.
While Troost-Ekong believes there is plenty more to come from 6ft 6in Okoye, he is in no doubt of the attributes his compatriot will bring with him to Hertfordshire, and he is confident his style of play is suited to that of the English top flight.
“Among his main strengths is his size, and he is still very mobile and confident coming for balls in the box despite that,” added Troost-Ekong.
“I think he’s definitely got the size and strength to be successful in the Premier League. He’s good on his line, he’s strong and he’s got a good kick, so he’s got everything he needs.
“He’ll be the first to say he’s still improving, but he’s very open to learning and he’s always looking out for advice, so I know he’s only going to improve going forward and I can’t wait to welcome him to London Colney.”