London, Feb 25 (IANS) Veteran actress Helen Mirren says she learnt how to smile in her "mid-thirties".The 71-year-old avoided smiling at people for over three-decades because she thought she looked "stupid" when the corners of her mouth turned upwards, but after she urged herself to grin more, she noticed it instantly made her feel "a little bit better", reports dailymail.co.uk."It was only actually in my mid-thirties that I learnt to smile. I couldn't smile before that, I thought I looked stupid when I smiled," Mirren told Victoria Derbyshire on her show."And then I learnt the power of a smile and funnily enough when you smile, even if you don't feel like smiling, you immediately feel a bit better. Life feels a little bit better when you're smiling," she added.