Appearing at The Global Travel Conference in La Manga, Spain, the star of BBC TV show The Cruise said that agents’ personal experiences of cruises were crucial to selling holidays.

McDonald told delegates: “You are vital to creating the perfect holiday, as you’ve experienced it. You’re experience is vital to customers.”

McDonald, who recently appeared on Channel Five’s Cruising with Jane McDonald, has been on more than 40 cruise holidays, and praised the industry for its “second-to-none service.”

She described Viking Ocean Cruises, Royal Caribbean and Silversea as “amazing” ocean liners, and also spoke highly of her recent river sailing with Uniworld.

She described river cruises as “all about getting into the cities and going off exploring,” making them suited to active – and younger - clients, while ocean cruises offered “entertainment and glamour”.

Meanwhile, discussing her own career path, McDonald said self-belief and a readiness to “fake it till you make it” had helped bring her success.

“Believe in your product and sell it as if it’s the best thing in the world, then it will be” she advised travel agents.

She added that having a supportive team in place helped to breed success. “Have likeminded people – and people that you like, and that like you – on your team,” she said.

McDonald also encouraged agents to be ambitious and to go after their dreams. “Take chances and aim high – and if it doesn’t work, it doesn’t matter,” she added.