The agreement follows speculation about deal.
2024 CMO Report reports rise in proportion of marketers who agreed that AI ads can 'truly move people.'
Lego, which recently concluded an 18-month media agency review, also appoints Mother's Marina Banks to operations role.
Jansen will take over the role in January.
Group forecasting full-year organic growth of 1%, a downgrade on its previous forecast.
Deal agreed by boards of Informa and Ascential but subject to regulatory and shareholder approval.
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