Sienna Miller delighted in shocking people by kissing her boyfriend while wearing prosthetics designed to make her look older.

The 37-year-old actress was aged up for her role as Beth Tilson Ailes in miniseries 'The Loudest Voice' and she loved going out disguised as her alter ego, especially when she was with her partner Lucas Zwirner.

She said of the character: ''I used to take 'her' for walks and into bars. I walked down the street with my quite young-looking boyfriend and asked him to kiss me passionately in front of a crowd of tourists.

''They were horrified at the sight of this young boy kissing his nanna!''

Sienna - who has seven-year-old daughter Marlowe with former partner Tom Sturridge - can next be seen as a single mother hunting for her missing daughter in 'American Woman' and was excited to find out it was her first major role without a supporting male co-star.

Speaking to talk show host Graham Norton, she said: ''It occurred to me as I was filming that I had never been on my own in a lead role before.

''I had an amazing cast supporting me but for the first time I didn't have a man to lean on.''

The 'Factory Girl' star recently admitted she likes to ''disappear'' into her roles because they provide a welcome distraction from real life.

She said: ''It's very relieving ... turning down the noise on your own life and shifting the focus to what it would be to be someone else. You do cease to exist. There's real peace in that ... I also do like being myself. I'm not filled with self-loathing and trying to escape it, but I just ... I like disappearing.''

The full interview with Sienna airs on 'The Graham Norton Show' on BBC One on Friday (11.10.19) night.