Liz Kendall has been given a post-bank holiday boost after Chuka Umunna backed her Labour leadership campaign.
Umunna, who dramatically dropped out of the race, said he endorsed Kendall because the shadow care minister could take Labour beyond its comfort zone.
The shadow business secretary co-authored a pro-Kendall article for the left-wing publication New Statesman alongside fellow Labour MPs Emma Reynolds, Jonathan Reynolds and Stephen Twigg.
The group argued the 43-year-old had "asked the tough questions and started to chart a course to the answers" on "all of the big subjects".
"She has been courageous in challenging conventional wisdom. She has no compunction in moving Labour beyond our comfort zone and is determined to build a team ready to chart a route forward," the piece claimed.
"This is exactly what our party needs and that is why we are nominating her to be the next leader of the Labour Party."
Labour's shadow education secretary, Tristram Hunt, is another high-profile backer of the Kendall campaign.
But the former special adviser is expected to face stiff competition from the likes of Andy Burnham and Yvette Cooper. Mary Creagh, the shadow international development secretary, is also in the running.
Burnham has had his own high-profile backers in the early stages of the contest. In particular, Barnsley Central MP and former Army officer Dan Jarvis has given his support to the 45-year-old.
Lord Prescott, who threw his support behind Burnham, recently blasted the Labour leadership contenders for their apparently trite language.
"What the hell does that mean, aspiration? I hear a lot of the candidates talking about it, they've clearly got aspiration, but what the heck does it mean?" the former deputy prime minister told Radio 4's Today programme.
Labour's parliamentary party nominations period closes tomorrow (27 May) and candidates will need the signatures of 35 MPs to pass on to the next round.
Ed Miliband's successor will eventually be unveiled on 25 September when the ballot result is announced.