Ahead of their trip to the London Stadium, Brighton have registered eight points from eight games since earning promotion from the Championship earlier this year.
Bilic has acknowledged that the away form of Chris Hughton's side is "not so good", but insisted that he expects a tough game against the Seagulls on Friday night.
The 49-year-old told reporters: "They also improved after a slow start. Their home form is good, but their away form is not so good.
"I watched their games and I can see a very confident team, because they got that confidence last season when they were winning lots of games. They spent most of the season top of the table.
"They have confidence, a pattern and brought some good players from Holland and Germany."
Brighton currently sit ahead of West Ham in the league table on goal difference.