Tennyson, 22, will challenge Walsh for his belt at the Copper Box Arena.
Known as 'The Assassin' he has a 16-1 record with 13 knockouts since turning pro in September 2012 and joined Warren's stable on Monday.
"It's massive, I feel this move could bring my career to the next level," Tennyson said.
"Beyond British title fights, I believe Frank Warren can bring me bigger and better titles in the future."
Tennyson is the mandatory challenger to Walsh after dispatching Antonio Horvatic inside a round in Belfast last month.
His British featherweight title fight is on the undercard of Billy Joe Saunders' first WBO middleweight world title defence against Ukraine's Max Bursak.
"I'm not expecting to go in and blow Ryan Walsh out of the water because he's a good fighter, and he's the British champion for a reason," said Tennyson.
"I'm going to go in and get the job done regardless, but I'm training for 12 rounds."

Burberry reported pre-tax profits of £166m for the year to March. A year ago it made a loss of £16.1m, hit by charges at its Spanish operations.
In the past year it has opened 21 new stores and closed nine. It plans to open 20-30 stores this year worldwide.
The group has also focused on promoting the Burberry brand online.
Sales rose 7% to £1.28bn, with the company recording double-digit sales growth in Europe and Asia Pacific.
Adjusted profit rose 23% to £215m, taking into account one-off items and a favourable exchange rate.
Stores in London in particular benefited from favourable currency movements and increased tourism.
"Looking forward, while mindful of the economic environment, Burberry plans to build on its strong financial position by accelerating investment in growth initiatives in retail, digital and new markets, while continuing to enhance the brand," said chief executive Angela Ahrendts.
Burberry shares were up 7.6% at 659 pence in afternoon trading.
Belfast featherweight James Tennyson will fight Ryan Walsh for the British title in London on 30 April after signing with promoter Frank Warren.
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Luxury fashion designer Burberry has returned to profit after opening new stores and spending more on online marketing