Named Grand Relax, it is designed to offer "outstanding comfort", with an understated, compact and slender form.
"The design of Grand Relax originated with the idea of creating a product in leather," explained Citterio.
"The process is different when you have leather in mind, as opposed to fabric – you can't simply adapt the design of a product conceived with a textile cover to one with leather," he continued.
"The idea was then to combine an external structural shell with very soft leather-covered cushions on top. Compared to the Grand Repos lounge chair, Grand Relax is smaller – and more importantly, has loose cushions," he added.
Vitra and Citterio designed the chair with thin cushions that slot into its low-slung body.
Combined with long armrests and tapering backrest, it is designed to create a relaxing feeling when the user sits down.
Grand Relax is also fitted with a mechanism that absorbs the bodyweight of the sitter, and in turn shifts the chair into a reclined position. The seat and backrest move independently to adapt to their user.
To manually control this mechanism, two levers are concealed either side of the seat.
While one of them adjusts the resistance of the mechanism, the other enables the user to lock the back in any angle.
The chair sits atop a four-star base, which is available in either polished or powder-coated aluminium, and allows the lounge chair to pivot by 360 degrees.
It is complete with a height-adjustable neck cushion, and a matching ottoman for use as a footrest or additional seating.
Vitra is a family-owned furniture company founded in 1950, and based in Switzerland. Other furniture collaborations by the brand include the Allstar chair designed with Konstantin Grcic and an office chair collection by Barber and Osgerby.
Grand Relax was presented on the Vitra stand at the Salone de Mobile in Milan earlier this month. Find out more about the collection at www.vitra.com.