The 44-year-old singer - who went solo when Take That disbanded in 1996 - thinks the 22-year-old pop star could initially find it hard starting off on his own but he's sure his family and friends will help him adjust to life outside of 1D.
Gary said: ''It's easier for the band to cope with but harder for (Zayn) going off on his own. I don't know what his character is but being in a group like that is a big high. However, he seems to have good people around him and family, so I am sure he will be fine.''
Gary knows more about the trials and tribulations of boy bands than most after seeing Take That in the last 25 years go from five to four members, break-up and return as a four-piece and then reform as a foursome, tour as a five-piece and shrink to three members for their latest LP 'III' over the last 25 years
With his decades of experience the 'Back For Good' hitmaker is sure the four remaining One Direction stars - Niall Horan, Harry Styles, Louis Tomlinson and Liam Payne - have a bright future because of their loyal fans.
Speaking to the Daily Mirror newspaper, Gary said: ''We have been a five-piece, then we were down to four and now there are just the three of us ... but our fans have been there for us the whole time. I imagine (One Direction's) fans are very similar.''
Despite having huge fame in the UK, Gary has never broken the US until now, having written and composed all the music for 'Finding Neverland', a Broadway production starring Kelsey Grammer and Matthew Morrison.
Speaking about the show, the former 'X Factor' judge said: ''I was very disappointed that America didn't happen (in 96). I was here for nine months doing a radio tour and went to every state and worked really hard but I didn't even have a glimmer of success. Sometimes the things that are unreachable just land at your door. That's how it feels this time around.''
We want to speak to the Grammys manager...