Royal Caribbean Cruises has announced that it will be investing in a major fleet wide upgrade program for Silversea Cruises.

The program, dubbed ‘Project Invictus’ is aimed at modernising one of the world’s most famous luxury cruise lines following Royal’s US $1-billion acquisition of a 66.6 percent stake in line.

Upgrades to entire fleet will bring Silver Muse standards to all Silversea ships.

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Royal Caribbean, the second-largest cruise company in the world, did not detail the enhancements or say how much it will spend, but did reveal that some ships would be entirely overhauled, while others would get more minor on-board tweaks.

“Our intent is to solidify our already strong leadership position with an exciting array of upgrades that thrill our guests,” Silversea CEO Roberto Martinoli said in a press release.

What has been revealed should whet the appetite of loyal Silversea cruise passengers.

Silver Muse, the line’s newest ship, will receive an improved “champagne and caviar offering” from mid-August onwards.

In December, the line’s 17-year-old Silver Whisper will go into dry-dock for a major refurbishment. All staterooms will be upgraded and public areas will be redesigned or refreshed, according to Royal Caribbean.

Silversea’s oldest ship Silver Whisper will be first to go under the knife.

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“Immediately thereafter, these and other enhancements will be implemented fleet wide, impacting a wide variety of on-board features and strengthening Silversea’s reputation for indulgent, luxurious embellishments,” Silversea said in a press release.

Silver Wind will follow, getting its own upgrades in December, and Silver Shadow will be last, although the date of her dry-docking has not yet been announced. The company said the changes are part of a plan to include popular features from Silver Muse on ships across the fleet.

Royal Caribbean’s investment in Silversea mirrors the enhancements made to Seabourn after it was acquired by Carnival Corporation in 2001. During the first decade after its acquisition by Carnival, Seabourn sold off the smallest and oldest ships in its fleet and ordered a fleet of new all-suite liners.

Royal Caribbean is the second-largest cruise company in the world, second only to Carnival, but had no pure luxury line like Carnival until the acquisition of Silversea.

Silversea Cruises and Seabourn Cruise Line are widely regarded as the two dominant ultra-luxury cruise lines, and the acquisition and planned upgrades continues Royal Caribbean’s longstanding rivalry with Carnival Corporation.