Michael Douglas thought he looked too young to play his character's age in 'Ant-Man'.

The 70-year-old actor - who is starring as Hank Pym in the new Marvel superhero film - has to play a younger version of his character in flashbacks, and said he was worried people would start thinking he looked nine-years-old in the shots where he discovered the serum.

Michael said: ''We got realistic about it, you know. They were going to go up to 75, and then it was like try to stick with the comics '60s and then it was 50 years, and then I said, 'Look, I don't want to be vain, but I'm worried, I mean, I look OK for my age'. I'm worried people are going to start to say, 'Was he nine when he made the serum?'''

The 'Behind the Candelabra' actor is starring as Paul Rudd's mentor in 'Ant Man', and described his co-star as ''brave'' and ''funny''.

Speaking to Collider, Michael said: ''He's great, you know. He has his thing. Once you get somber or sober or schmaltzy, you know, he's going to find a humorous way to end it and he's not afraid to put his face in the pie.''

Michael added: ''He's very brave. You know, he's very brave, funny.''