Alexander Gregor Pennie, or Pennie is lead vocalist of Welsh indie electro pop band Decimals. Pennie was previously in Welsh band The Automatic, where he provided backing vocals as well as playing synthesizers and keyboards for the act. Pennie left The Automatic in late 2007.

Alex is recognizable for his high pitched vocals and screaming he provided in The Automatic; however, since working with Decimals, he mainly provides melodic vocals.