Observations' One To Watch: Bel Powley, Actress, 20 Most actresses her age would be starting drama school - but not Bel Powley, whose West End appearance as Tamsin Greig's scantily clad and moody teenage daughter Tilly in Jumpy is the third play under her belt. The was in the Royal Court's Tusk Tusk in 2009 and a revival of Arcadia on Broadway last year. Next, she stars in the feature film The Nanny State about a sister and her little brother, due out later this year.