Sir Gerald, originally from Llansaint, Carmarthenshire, played for Cardiff, Llanelli and London Welsh and, after his retirement in 1978, he became a highly-respected administrator in the sport.
He was Lions manager for the 2009 tour to South Africa and also served as Welsh Rugby Union president between 2019 and 2023.
“I am humbled by it and moved by the thought that somebody, somewhere, has thought it worthy of giving me that honour,” he said.
“I feel very emotional about it. I am surprised by it. Words are really quite inadequate to describe it.”
He said he was grateful for the “enormous support” of his wife Cilla and children Emily and Ben, as well as friends and colleagues, adding: “They are constantly at my side in giving me support over the years. It is not something that you achieve entirely on your own.”
He was made a CBE in 2003, which also included recognition for his work off the rugby field.
He said life was now “nice and calm”, but that “rugby will be part of my life forever”.