U.S. President Donald Trump said on Tuesday he was open to billionaire Elon Musk buying social media app TikTok if the Tesla CEO wanted to do so.

TikTok Chief Executive Officer Shou Chew attended President Donald Trump’s inaugural events in Washington, appearing at a church service before the swearing-in ceremony as his popular video-sharing app faces the threat of a nationwide ban.

The app’s availability in the U.S. has been thrown into jeopardy over data privacy and national security concerns.

Perhaps the least well-known of the tech chief executives in attendance is also the most surprising: TikTok CEO Shou Chew. In his first term, Donald Trump tried to ban the Chinese-owned app as a threat to national security.

TikTok CEO Shou Zi Chew, in a video message posted to the platform after the Supreme Court ruling upholding the U.S. law that threatens to ban the app, thanked President-elect Trump for his support in trying to find a workable outcome to keep the app legal.

TikTok’s CEO Shou Zi Chew was seated next to Tulsi Gabbard, President Trump’s nominee to be the director of national intelligence, at the Capitol as Trump was sworn-in. The seating at the Capitol Rotunda was tight,