Carter was in a relationship with writer/director Tim Burton and has appeared in all of his films since 2001 except for Frankenweenie until their divorce in 2014. They have two children. In the past, she has also been involved with Kenneth Branagh, Rufus Sewell, and Steve Martin. She played the villainess Serena Kogan in Terminator Salvation.
- Helena took the role of Serena Kogan because her boyfriend at the time, Tim Burton, is a big fan of the Terminator franchise.
- Filming was delayed for a few days due to the untimely deaths of four of Helena's family members in a minibus accident.
- Tilda Swinton was also considered for the role of Serena.