The 38-year-old, France's all-time record goalscorer, left MLS side Los Angeles FC last week.

Olivier Giroud last played in the French top flight for Montpellier, winning the 2011-12 Ligue 1 title before leaving for Arsenal.

"I'm very happy and excited to be back in France, home," Giroud said in a statement.

"It made perfect sense to return to Ligue 1 13 years after leaving it. I've always considered Lille at top French club.

"It's a young and talented squad, which needs experienced players like me. So I'll also be there in that role."

Giroud spent six seasons with Arsenal, scoring more than 100 goals for the London giants before signing for Chelsea, with whom he won the 2021 Champions League title.

He then spent three seasons with AC Milan, lifting the Serie A crown in 2022, before making the move to the US.

Giroud retired from international football last year with a record 57 goals in 137 appearances for France and won the 2018 World Cup with the national team.