A Francis Bacon triptych depicting his friend Lucian Freud could set a new record for the artist’s work when it goes to auction for the first time.

Auction house Christie’s will next month sell the 1969 painting, which was first shown to the public four decades ago.

The work of Bacon – who died in 1992 – set a contemporary art record in 2008 when his painting triptych achieved a £43 million price at a sale.

Three Studies is one of only two surviving triptychs which Bacon painted of his associate Freud, uniting two of the foremost names in British figurative art of the 20th century.

It was first exhibited in 1970 and for a 15-year period the panels were separated, but were brought back together for a 1999 exhibition in the US and have been united ever since.

The only other surviving Bacon triptych of Freud dates back to 1966, and another from two years before that was permanently dismantled and put into different collections.

Francis Outred, head of postwar and contemporary art at Christie’s Europe, said: “Three Studies of Lucian Freud, executed in 1969 is a true masterpiece that marks Bacon and Freud’s relationship, paying tribute to the creative and emotional kinship between the two artists.

The juxtaposition of radiant sunshine yellow contrasting with the brutal physicality and immediacy of the brushstrokes makes Bacon’s art so remarkable

“The juxtaposition of radiant sunshine yellow contrasting with the brutal physicality and immediacy of the brushstrokes in this celebrated life-size triptych is what makes Bacon’s art so remarkable.”

Three Studies will be on view at Christie’s King Street in London during Frieze Art Week which runs until Friday, before being auctioned in New York on November 12.