The two ships, which will continue to operate under the Crystal Cruises brand which has also been acquired by the group, will resume service in 2023 after undergoing refurbishment.
Silversea founder and co-chair of A&K Travel Group, Crystal Cruises and Abercrombie & Kent, Manfredi Lefebvre d’Ovidio, said he "did not think twice" when the opportunity arose to acquire the brand.
"I am thrilled to start this new chapter and to be back in an industry that has always had, and always will have a special place in my heart," he added.
"Thirty five years ago, my family acquired control of Sitmar Cruises, building three of the first purpose-built cruise ships, and 30 years ago my family pioneered a new way of cruising.
"Selling the cruise business that belonged to my family for a quarter of a century was a difficult decision, as I knew I would miss this industry immensely."
Geoffrey Kent, co-chair of A&K Travel Group and Crystal Cruises, and founder, co-chair and chief executive of Abercrombie & Kent, said the company will combine the onboard service Crystal "is known for" with the tailor-made experiences Abercrombie & Kent offers.
Crystal Cruises and Abercrombie & Kent will report to former Silversea Expeditions managing director and chief executive of A&K Travel Group Cristina Levis, who said: "My return to luxury cruising after five years brings back so many emotions.
"It is an immense privilege to serve these two incredible brands that in the past decades have disrupted the travel industry numerous times."
The two vessels were auctioned for $128 million earlier this month after they were put up for sale in the latest of a series of steps in the liquidation of parent company Genting Hong Kong.
