Gordon Sondland, the U.S. ambassador to the European Union and a key witness in the House Democrats’ impeachment inquiry, is ready to testify to Congress this week that a text message he sent to fellow diplomats defending President Trump against wrongdoing in his Ukraine dealings was actually relayed to him by Trump himself, according to The Washington Post.

A source cited by the Post said Sondland plans to tell lawmakers that he can’t vouch for whether or not the president was honest when he said there was no quid pro quo in his urging the Ukrainian president to investigate former vice president Joe Biden. “It’s only true that the president said it, not that it was the truth,” the source was quoted as saying of Sondland’s testimony.

Trump and his allies have pointed to Sondland’s words in the Sept. 9 text exchange—in which he shot down a fellow diplomat’s suggestion that Trump was withholding security aid to Ukraine in order to force the country’s hand on Biden—as proof that the impeachment inquiry against Trump is nothing more than a witch hunt. In that exchange, Sondland took several hours to respond to a suggestion by Bill Taylor, the top U.S. diplomat to Ukraine, that Trump was leveraging aid to clinch a political favor. When Sondland finally did respond, he told Taylor he was “incorrect.”

“ The President has been crystal clear: no quid pro quo’s of any kind. The President is trying to evaluate whether Ukraine is truly going to adopt the transparency and reforms that President Zelenskiy promised during his campaign,” Sondland said.

The Washington Post now reports that Sondland had contacted Trump before responding, and Trump told him he “didn’t want a quid pro quo.” That call is said to have last less than five minutes.

Sondland is also expected to say during his testimony on Thursday that he spent months prior to the September text exchange working at Trump attorney Rudy Giuliani’s direction to get Ukrainian authorities to announce publicly that they would be investigating corruption at the Ukrainian gas company linked to Biden's son.

In exchange for that announcement—described as the “deliverable” in the text messages—Ukrainian President Volodymyr Zelensky would finally get the White House meeting he'd been seeking, according to the Post.

“It was a quid pro quo, but not a corrupt one,” the person familiar with Sondland’s testimony told the Post.

Giuliani has publicly claimed that his discussions with Ukrainian officials to push for a Biden investigation were facilitated and directed by the State Department. But according to the whistleblower complaint that sparked the impeachment inquiry against Trump, State Department officials including Sondland and former U.S Special Envoy to Ukraine Kurt Volker had talked to Giuliani in a bid to “contain the damage” of his shadow diplomacy in Ukraine.

Sondland, a political appointee who donated $1 million to Trump’s inaugural committee, was blocked by the State Department from appearing for a deposition earlier this week, a move which Trump all but confirmed in a tweet declaring he didn’t want his ambassador to testify “before a totally compromised kangaroo court.”