The England Under-21 striker, who bagged 10 goals for the Hornets this term, completed a last-minute move to the Premier League club as the January window prepared to slam shut on Tuesday night.
And Sordell used his Twitter account to show his support for his former employers. In a series of tweets, he said: "Thank you everybody for the kind messages. Sad to be leaving Watford but it's a new chapter in my career that I'm delighted to be starting.
"I loved every minute at the club and will never have a bad word to say about anybody there. I'd like to thank everybody at the club. And in particular the manager Sean Dyche for guiding and helping me to improve as a player and a person.
"I wish the club all the best for the future. I'm very excited to have the opportunity to play for Bolton in the Premiership and I can't wait to get started now. I'd also like to thank the fans for all the support I've had over the years. You've been great to me and I loved scoring goals for you!"
Watford centre-back Adrian Mariappa remained at Vicarage Road despite a host of top-flight interest, while fellow defender David Mirfin returned to former club Scunthorpe on loan for the rest of the season. Matthew Whichelow also joined Wycombe on a one-month loan deal.
