Has there ever been any one won an acting Oscar and a UK number single?

Yes, there have been a few people who have won an acting Oscar and also had a UK number single. Here are a few examples:

1. Barbra Streisand: Won an Oscar for Best Actress for "Funny Girl" (1968) and had a UK number-one single with "Woman in Love" (1980).

2. Cher: Won an Oscar for Best Actress for "Moonstruck" (1987) and had a UK number-one single with "Believe" (1998).

3. Jamie Foxx: Won an Oscar for Best Actor for "Ray" (2004) and had a UK number-one single with "Gold Digger" (2005).

4. Eminem: Won an Oscar for Best Original Song for "Lose Yourself" (2002) and had a UK number-one single with "Stan" (2000).