https://www.youtube.com/watch?v=aZnPazOC-zI
Netflix’s One Day at a Time already announced that Gloria Estefan will be a guest on the third season, and now KSite is reporting a cast member from the original series will also be appearing on the show this season. Glenn Scarpelli, who played Alex in the later seasons, will be playing Chad on this show. No other details are known at this time. But I can tell you the actor looks the same, except now he has salt and pepper hair.
He is not the first actor from that series to work on ODAAT. Mackenzie Phillips, who played Julie, has appeared on a few episodes while her husband from the sitcom, Michael Lembeck has directed an episode. Why Valerie Bertinelli has no guest starred on it is a mystery for me.