The reshuffle follows the abrupt departure of CEO Bernard Looney last week after he did not fully disclose past relationships with colleagues.
Thomson, who joined BP nearly 20 years ago, previously headed the finances of the energy giant’s oil and gas production and operations division.
She has been a member of the board of Aker BP (AKRBP.OL) for the past seven years and also serves on the boards of a number of BP group companies.
Looney’s departure sparked an urgent search internally and externally for a new, permanent CEO, with no clear front-runner.
“Kate’s experience and skills make her ideally suited to take on the role of interim CFO. She brings deep technical knowledge together with a detailed understanding of BP,” Auchincloss said in a statement.
Auchincloss, 52, worked closely with Looney in devising BP’s energy transition strategy and has advocated a focus on high-return assets to finance the transition, according to two company sources.
BP’s legacy oil and gas assets boosted profits to a record $28 billion last year.
Reporting by Yadarisa Shabong in Bengaluru and Ron Bousso in London; editing by Rashmi Aich