Dominic Cooper thinks ''old-fashioned attitudes'' towards gay actors still ''linger'' in Hollywood.

The 40-year-old star - who has previously dated the likes of Amanda Seyfried and Ruth Negga - has admitted to being saddened by some of the attitudes that still exist within the movie business.

He shared: ''It still seems prohibitive. People [feel] nervous because of the old-fashioned attitudes that linger.

''It makes me so sad. We're making slow changes and I hope that we're becoming more fluid with our thinking.

''It's all so prehistoric. It astounds me. Youngsters are completely unfazed, they don't even blink.''

Dominic - who identifies as straight - drew a parallel between the film industry and those in the sporting world.

Speaking to Attitude magazine, he explained: ''Things are changing and along with that will come the attitude towards who you need to be in Hollywood. And sport.

''Look at sports personalities who don't feel confident or comfortable enough to do it. A life not being who you can be must be very difficult.''

Dominic stars alongside Cher in the money-spinning 'Mamma Mia!' film franchise.

And he's revealed that the veteran star was extremely nervous on her first shoot for the new 'Mamma Mia! Here We Go Again'.

He said: ''She felt quite nervous. She's an Oscar winner, a brilliant actress and a phenomenal singer, and she had Julie [Walters] and Christine [Baranski], who are so easy, they're going to make it comfortable.

''Even so, you're still going to get anxious when you arrive on set. That's the truth. It's a big thing to do. She was very open to wanting support and help.

''We all knew that because we've all been there. Not one of us hasn't had that feeling of walking on to something that you weren't part of originally. We all knew each other so well and she didn't.''