The pair will appear in Rufus Norris's adaptation of the beloved musical, which is taking up a 15-week residence in London's Savoy Theatre from October 3 following a month-long regional tour.
Young will take on the role of Emcee, while ex-EastEnders actress Ryan will play leading lady Sally Bowles, the character made famous by Liza Minnelli in the 1972 film version.
Esteemed actress Siân Phillips, whose credits include the original BBC version of Tinker, Tailor, Soldier, Spy and I, Claudius, has also joined the cast.
Speaking upon the announcement of his casting in May, Young stated: "I am very excited about the challenge of choosing Cabaret as my first musical theatre role.
"I have spent the last ten years singing, dancing and acting all separately. For the first time I get to do all three in one show. How could I not be excited?"
Cabaret will first play at Bromley's Churchill Theatre on August 30, before heading to Southampton, Nottingham, Norwich and Salford Quays.
Seats for the London performances begin at £35 and can be purchased through ATG Tickets.
Watch Liza Minnelli perform in Cabaret below: