Matt Bomer has been warned by doctors to try not to lose and gain weight rapidly for movie roles.

The 39-year-old actor had to lose an excessive amount of body fat for 2014's 'The Normal Heart' and back in 2012 he had to buff up and gain 20 pound to portray stripper Ken in the first 'Magic Mike' film.

However, medical professionals have advised him that it's not good for his health to drastically yo yo between sizes.

He said: ''I was just discussing it with my doctor yesterday and he said, 'You know, I wouldn't do anything like that in the near future. I'm not saying you can never do it again, but just don't do it any time soon.'

''There was a period there where I was losing 40 pound for Normal Heart and then putting on 20 pound for Magic Mike. It just got a little crazy and your body is going, 'What's going on?'''

Despite the health concerns, the dark-haired hunk insists he finds it easy to hit the gym and work on building muscle because of the strict training he had when he played on a football team when he was younger.

He told website MR PORTER: ''Twenty minutes and, if you do it right, you're drenched at the end of it. I still have that super-ego voice of all those Texas football coaches in my head any time I'm doing anything physical, so I can usually push myself solo pretty well.''

Meanwhile, the 'White Collar' star has three children, Walker Bomer, Henry Bomer and Kit Bomer, born via a surrogate mother - who he fathers with his husband Simon Hall - and says he loves to spoil them with gifts when he's away working.

He said: ''I do so much guilt-induced shopping for the kids when I'm gone on location, I'm firmly convinced that Amazon hired me because they know how much I've spent on their website.''