The striker has agreed a one-year contract with the option of a further 12 months.
Inverness have confirmed the signing of Tade, but manager Terry Butcher told his club’s official website: “Maurice Malpas and I have been going flat out speaking to players and agents then faxing contract offers.
“We’re making headway but although players out of contract became free agents on 1st June, the transfer window does not officially open until 9th June, the date at which the Scottish Football Association accept registrations.
“One or two clubs may have announced signings but players cannot legally be signed and registered before 9th June. Most managers, myself included, will wait until then.”