.The pair played against Forest in the Terriers' Championship play-off final defeat last season.

O'Brien, 23, had been with Huddersfield since he was 11 while Toffolo, 26, has blossomed at left-back since joining from Lincoln two years ago.

"To join a football club with this much stature is fantastic," said Toffolo.

"I'm extremely delighted to be here. To have the opportunity to play in the Premier League is something I couldn't turn down.

"I'm excited, really looking forward to meeting the lads and pushing forward in this division. We've got a fantastic squad being put together.

"I'm a player who wears his heart on his sleeve and I'm someone that will fight for the badge and for the team every single minute. I can't wait to get started," he added.

The former England Under-20 international had one year left on his Huddersfield contract.

O'Brien, whose signing was announced shortly after Toffolo's, said: "Having played at The City Ground last season I've experienced the atmosphere, and when the opportunity came about to join Forest it was a no-brainer for me.

"You only have to look at Forest's turnaround last season to see that something special is happening here at the moment, and after my first conversation with [manager] Steve Cooper it was obvious we both share the same vision. I'm buzzing to be part of the project.

"The fans turn out in their numbers week after week and they've waited so long for Premier League football. It's now up to myself and the rest of the team to make sure we keep a smile on their faces."

Forest's win over Huddersfield in the Championship play-off final saw them return to the Premier League for the first time in over two decades.