The striker penned a lengthy five-year deal with the Foxes that will see him remain at the club until June 2021 and, while the official announcement did not disclose a fee, the hefty price tag is believed to be a club record fee upwards of £25-million.
He joins fellow Algeria international Riyad Mahrez at the King Power Stadium as the club looks to mount a credible title defence following on from their heroics last season.
"To join a team like Leicester City is a huge honour and I can't wait to get started. I've always wanted to play my football in the Premier League and to get the opportunity to do that with the reigning champions was something I simply could not turn down," Slimani told the club's official website.
"My friend Riyad Mahrez spoke to me about the Club and about the atmosphere the Leicester fans create at King Power Stadium. I will give absolutely everything I have on the pitch for them and for my team-mates and I hope that together we can achieve something special."
The striker has is famous for his work-rate and determination, two key attributes their success in the 2015/16 campaign were based around and manager Claudio Ranieri will be eager to see what he can do in training.