Ex-centre Littlejohn, who captained Scotland Women and scored the decisive try as they defeated England at Inverleith 8-5 to secure their first grand slam in 1998, stars on the £1.70 stamp.
Scrum-half Roy Laidlaw, whose two first-half tries against Ireland in Dublin in 1984 were instrumental in Scotland winning their first triple crown since 1938, features on the first-class stamp.
The eight stamps in the set mark the 150th anniversary of the first international rugby match, staged between Scotland and England at Raeburn Place in Edinburgh in 1871.
Littlejohn remembers the excitement at Christmas as a child when designs for new stamps would be unveiled. “It never crossed my mind that I would end up on a stamp, but if it was going to be from anything, it would be from rugby because that was my passion,” she said.
“Being on the stamp is about representing everybody else who was part of that team on and off the field – the players, the coaches and everyone else involved.”
Routinely, Littlejohn doesn’t recall much from specific matches during her test career – but she vividly remembers parts of that 1998 match in Edinburgh.
“I remember lining up for the anthems and facing the stand,” she said. “It was huge, the fact it was England in that final game. It was kind of a storybook setting. It still gives me goosebumps.”
And for the stamp to appear just days after Scotland Women kept their Rugby World Cup qualification hopes alive was not lost on Littlejohn.
“The win against Ireland was a great advert for women’s rugby,” she added.
“I messaged Bryan (Easson, the Scotland Women’s head coach) to say how brilliant it was and I really hope they will take momentum from that.”
The set of stamps also features JPR Williams, Emily Scarratt, Danielle Waterman, Sophie Spence, Simon Geoghegan, Melissa Berry and Jonny Wilkinson.
They are available to pre-order now at www.royalmail.com/rugbyunion and go on general sale on October 19.