Dennis Hardy "Fergie" Frederiksen (born May 15, 1951, Grand Rapids, Michigan) is an American rock singer whose career peaked during the 1980s, having stints with several notable rock bands including Angel, Le Roux and Toto. He first broke out in the mid to late 1970s fronting Chicago pomp rock bands MSFunk and Trillion, and was also a background vocalist for Survivor. He contributed to hit singles in three consecutive years, all with different bands: Survivor's "American Heartbeat" in 1982, Le Roux's "Carrie's Gone" in 1983 and Toto's "Stranger in Town" in 1984.
Frederiksen started his musical career at the age of 13, and he played clubs and pubs at the age of 15 with a group called the Common People in Grand Rapids, MI. In 1975, while he was still attending college at Central Michigan, Frederiksen was asked by his friend Tommy Shaw to replace him as the lead vocalist for the band MSFunk, as Shaw was leaving to join Styx. Frederiksen was with MSFunk for a year before disbanding in 1976. While living in Chicago, he helped form a local progressive rock band called Trillion with keyboardist Patrick Leonard. Trillion's debut album was released in 1978 and was produced by Gary Lyons (producer of Foreigner's debut album); all but one of its nine tracks were co-written by Frederiksen. The band went on to tour with Styx and Heart, where Frederiksen began performing his trademark back-flips during live shows to fire up crowds, a gimmick he would continue with later bands. Frederiksen would leave the group after one album, and was replaced by Thom Griffin.