The agreement follows the completion of a £20m refurbishment at the venue, which saw its lower galleries redeveloped. The new look Galleries of Modern London, which opened recently, tell the story of the capital from 1666 to the present day and are available for evening hire.
"The space is incredible and unbelievably flexible," said The Finishing Touch managing director, Mel Atkins.
"Guests can experience a vision of London’s past and present while enjoying fine cuisine and a selection of beverages. We can cater for up to 550 for a dinner or as many as 1250 for a reception. We are also creating an Olympian nightclub for guests to dance the night away."