Howard Dean, the former Democratic candidate for president, and Michael Steele, the ex-head of the Republican National Committee are joining the advisory board of Tilray Inc., the Canadian cannabis grower, the company has announced.

Backed by Silicon Valley billionaire Peter Thiel, Tilray was briefly worth more than $28 billion -- valued at more than Twitter or CBS -- in September after it became the first cannabis company to be listed on an American stock exchange. The company made a second splash this year when it was chosen by the U.S. Drug Enforcement Agency to provide a small amount of marijuana for a study at the University of California, San Diego.

Dean, a former physician, served as governor of Vermont for 12 years before running for president. He later became the head of the Democratic National Committee. Since 2015 he has been affiliated with the the world’s largest law firm, Dentons, as part of its public policy and regulation practice. Steele once served as the lieutenant governor of Maryland and has been openly critical of the current presidential administration.

Dean and Steele join a host of other well-known politicians on the boards of marijuana companies. Former Speaker John Boehner serves on the board of Acreage Holdings along with former Massachusetts Gov. Bill Weld. Former heads of state working with weed concerns include former Canadian Prime Minister Brian Mulroney (also with Acreage) and former Mexican president Vincente Fox serves on the board of Khiron Life Sciences Corp. a medical cannabis company with operations in Colombia.