Anglea Eagle stood in for Jeremy Corbyn and prime minister's questions on Wednesday - and Labour MPs loved it.
When David Cameron is out of the country, George Osborne takes his place at PMQs. As shadow first secretary of state, Eagle has the job of firing questions at the chancellor.
She was greeted with loud cheers from the Labour benches when she stood, and the backbenches lapped up her jokes at the expense of the Conservatives and Osborne's leadership ambitions.
"I notice he didn't answer the question about his own prime ministerial activities," Eagle told the chancellor. "He might be worried about somebody a few places down him on the bench."
Pointing at home secretary Theresa May, Eagle added with a wide grin: "She knows who she is."
Eagle added: "He so preoccupied with his own leadership ambitions he forgot about the day job. That's why he ended up trying to slash working families tax credits in the Budget. Isn't it about time he focused on the national interest rather than on his own interest?"
The veteran Labour MP, who has honed her joke telling skills at the far less box office weekly Commons business questions sessions, also deployed Corbyn's PMQs tactic of reading out a letter from a member of the public.
Eagle quoted president of the European Commission, Donald Tusk, who earlier this week wrote to Cameron to warn him Britain's EU renegotiation faced significant obstacles.
"I've got here a letter," Eagle said. "It's from Donald of Brussels. And he writes: 'Uncertainty about the future of the UK in the EU is a destabilising factor'. He's right isn't he."
Osborne was not prepared to let Eagle have all the jokes. "There's someone called 'Tony' who has been writing today. He happens to be the most successful Labour leader in history. He is describing the Labour Party as a complete 'tragedy'," the chancellor replied.
This morning the Spectator published an article by Tony Blair, in which the former Labour leader defended his record in government and criticised the direction of the party under Corbyn.
Eagle hit back, prepared: "I prefer this quote from Tony: 'Just mouth the words 'five more Tory years' and you feel you sense and reason repulsed by what they have done to our country'."
After Eagle made fun of Osborne for Tory backbenchers criticising the government's EU renegotiation plan, the chancellor joked: "I'm not sure I'd be quoting the views of backbenchers if I was speaking for the Labour Party at the moment. Most opposition parties are trying to get momentum they're trying to get rid of it."
Momentum is a Corbyn supporting grassroots campaign group which some centrist Labour MPs fear is behind moved to deselect them ahead of the 2020 general election.