The wrecking ball striker bagged 12 goals for the Blues in the 2024/25 Premier League campaign, sparking talk of an England call-up.

Chelsea triggered a £30m relegation release clause, but he struggled for goals at the West London club last season and subsequently joined Forest in a £50m deal back in the summer.

Speaking ahead of the hot-headed and powerful front man returning to Suffolk soil as an opposition player, O'Neil said: "I think the front three is dangerous, regardless of who it is. Delap, (Morgan) Gibbs-White, (Dan) Ndoye - just writing them down, it looks like it's going to be a threat, isn't it? It's going to be tough to stop.

"Liam will be part of that. He's physical and they use him a lot because they're a very, very direct team.

"You saw him giving Gabriel a tough time from direct play against Arsenal the other day.

"Some of the boys here know what he can do. Regardless of the fact that he was here, I've seen what he can do in recent weeks watching them.

"We're trying to prepare ourselves for what he brings. But we try and give the team a structure that protects us against that stuff. It's never about just trying to stop individuals."

Forest star Morgan Gibbs-White, who bagged 18 goals in all competitions last season, is set to return to the team after recovering from injury.

"He's a an England international, top player," admitted O'Neil.

"He always causes problems in every game he plays. He's bright, physically very good and has good tactical understanding. So I'm sure his manager will be delighted to have him back.

"They've got lots of good players, been in the Premier League for a while now, have managed to keep adding each window and spent good money on a new coach.

"So we expect Nottingham Forest to be a big challenge for us regardless of who plays and who starts.

"But we also know, as we've shown, that we can cause teams problems ourselves. We have our own good players. We have a strong bench. We have a way that we go about it. And we're hopeful that we can be the ones that come out on top."