One of the world's biggest tobacco companies is diving into the cannabis market with a $2.4 billion investment in Cronos Group, a Canadian medical and recreational marijuana company.

Altria, which makes Marlboro cigarettes, is taking a 45 per cent stake in the Toronto company.

Cronos said on Friday that the Richmond, Virginia, tobacco company will pay another $1.4 billion for warrants that if exercised, would give the Altria a 55 per cent majority ownership stake.

Cronos first announced that it was in talks with Altria this week.