NEW YORK (AP) — MSNBC announced Thursday that business journalist Stephanie Ruhle will replace Brian Williams on the nightly newscast "The 11th Hour," and that "Morning Joe" will expand to four hours.

Ruhle, who will continue as a senior business analyst across other NBC News programs, had been host of the 9 a.m. Eastern hour on the news network.

In a memo to staff, MSNBC President Rashida Jones said Ruhle will bring her "business acumen, hard-hitting interview style and original reporting" to the 11 p.m. Eastern hour. She's expected to keep the format Williams originated before leaving the network in December, with a review of the day's news and a centerpiece panel of three experts.

"Morning Joe," with Joe Scarborough, Mika Brzezinski and Willie Geist as hosts and a rotating panel of guests, currently airs from 6 a.m. to 9 a.m. Eastern. It will take over the hour Ruhle is vacating.

Jones said the expansion "will give us an opportunity to extend the reach of the program, which has become so well known for its signature perspective and analysis, as well as its newsmaking interviews."

The changes are expected to go into effect in a few months; no start date was given.