Zac Efron

Association: movie Hairspray

Ashley Tisdale
Association: Good friends

Selena Gomez 

Association: Friends

Ashley Benson
Association: Starred in Spring Breakers together

Vanessa Hudgens

Association: Starred in Spring Breakers together

Austin Butler
Association: Currently Dating

Jenette McCurdh

Association: both played in iCarly

Frankie Muniz
Association: Both were on Malcolm In The Middle

Hilary Duff

Association: Both in movie Agent Cody Banks

Haylie Duff
Association: They are sisters

Nick Zano

Association: Ex

Kat Dennings

Association: Dated.

Steve Carell

Association: Both in The 40-Year-Old Virgin

Jimmy Fallon

Association: Friends.

Joseph Gordon-Levitt

Association: They competed against each other on Lip Sync Battle and they are also friends

Scarlett Johansson

Association: movie Don Jon

Sean Penn
Association: Dated

Madonna 

Association: Oral Dated

^

Guy Ritchie
Association: Divorced

Robert Downey Jr.

Association: movie Sherlock Holmes.