The duo, who are currently coaches in the Hornets academy, will take temporary charge of the team for their trip to Hull alongside Adrian Mariappa.
Watford confirmed in a statement on Sunday that Gracia had resigned after meeting with owner Gino Pozzo, having said after their 2-0 defeat to Swansea on Saturday that he was seeking talks with Pozzo.
Read more:
The club said in a statement it was “sad and disappointed” that he had resigned.
Daniels and Gosling, though, along with Mariappa, will take the team when they visit Hull on Tuesday night.
Cherries legend Daniels made 265 appearances for the club across all competitions, after initially joining on loan from Leyton Orient in 2011, before signing on a permanent deal.
(Image: Sam Sheldon)
His time with Bournemouth saw them reach the Premier League, and he was a key figure in the team that reached the top flight and stayed there under Eddie Howe.
Gosling, meanwhile, was at the club for six-and-a-half-years before he departed for Watford in 2021, having made 192 appearances in that time.
He, too, helped Bournemouth achieve promotion to the Premier League, and he was an important part of the side in the first years in the top flight.