A major part of de Thame's modelling included appearances in TV ads.

By 1998, she had appeared in the mini-series Merlin and in the British feature film Bodywork; credited in both productions as Rachel Colover.

De Thame also co-presents the BBC's annual coverage of the Chelsea Flower Show, Hampton Court Palace Flower Show as part of the Royal Horticultural Society output on BBC Two.

Non-gardening related television appearances include Going for a Song and Call My Bluff, both for the BBC.

In 2008, de Thame designed the 2008 LK Bennett garden at the Chelsea Flower Show, for which she was awarded a silver medal.

In 2024 de Thame teamed up with her daughter Lauren, who is an illustrator, for her new book A Flower Garden For Pollinators.